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Mediaevistik 33 . 2020 89 2020 Bernard S. Bachrach, David S. Bachrach, University of New Hampshire 1 University of Minnesota Emeritus

1 Military Intelligence and Long-Term Planning in the 89 Ninth Century The Carolingians and Their Adversaries 112

2020 Abstract: Historians of warfare in the western tradition have devoted considerable attention to the problem of military intelligence from the Greek and Persian wars of the fifth century B.C.E. up to the recent past. Strikingly absent from this conversation, however, has been the treatment of the acquisition and analysis of information for military purposes in pre-Crusade Europe, particularly in the Carolingian and immediate post-Carolingian world. In part, this lacuna is the result of a general neglect by modern scholars of military matters in the ninth and tenth centuries. A second major reason for the lack of studies of military intelligence is the dead hand of nineteenth-century romantic-nationalist historiography that has imposed a “dark-age” straight-jacket on many aspects of the history of the early medieval world. This emphatically includes the history of warfare, which has been treated in the context of a putatively Tacitean or Beowulfian quest for honor and booty, rather than as a highly complex element of governmental activity. The present study addresses this gap in modern understanding of the complex nature of early medieval warfare through an examination of military intelligence in the ninth century with a focus on the Carolingians and their opponents, primarily the Vikings, the Muslim polity in Spain, and the Slavs. The study is divided into three parts that examine in turn, strategic intelligence, campaign intelligence, and tactical or battlefield intelligence.

Keywords: Carolingian warfare, Vikings, Slavs, Muslims, military intelligence, strategic in- telligence, campaign intelligence, tactical intelligence, long-term planning.

Historiographical Context

The scholarly traditions dealing with the conduct of war in both the Roman Empire and the Later Middle Ages have long recognized the crucial importance of examining in detail the matrix of questions regarding the gathering and analysis of military in- telligence for both short term and long-term decision-making.1 By contrast, scholar­ ship focused on the military history of early medieval Europe has been exceptionally reticent to engage with the problem of military intelligence. There are no monographs regarding this subject in the early Middle Ages. Moreover, there are just a small hand- ful of articles concerning military intelligence in the period between the end of the Roman Empire and the First Crusade.2 Even among this limited group of studies, none

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© 2020 Bernard S. Bachrach, David S. Bachrach https://doi.org/10.3726/med.2020.01.04 90 Mediaevistik 33 . 2020 consider in detail the ninth century, which is the focus of the present study, particularly after the death of Charlemagne in 814.3 The reluctance to engage with the problem of military intelligence is due to several factors. First, the military history of the Regnum Francorum in the century follo- wing Charlemagne’s death has suffered significant scholarly neglect in comparison to the preceding period.4 There are, for example, no published monographs on the armies and military organization of Charlemagne’s son Louis the Pious (814‒840), his grandsons Lothair I (840‒854), Louis the German (840‒876), and Charles the Bald (840‒877), or any of their sons and further descendants.5 As a consequence, many of the most basic questions regarding the organization and conduct of war in the ninth century within the lands of the Carolingian Empire, its successor realms, and along its frontiers have yet to be asked, much less answered.6 As a corollary to the comparative dearth of detailed studies of warfare and military organization in the post-Charlemagne Regnum Francorum, many of the limited discussions of the military history of this period perpetuate a “dark-age” model, first developed by na- tionalist historians in the nineteenth century, that emphasizes the putative existence of a booty-hungry warrior society mirroring the world of Tacitus’s Germania, or the Beowulf poet, often on the basis of the misrepresentation of both the written and ma- terial sources.7 This effort to present early medieval warfare as primitive, small-scale, and lacking any aspects of what today we would call military science, has limited interest in sophisticated aspects of the conduct of war such as military architecture, logistics, training, military education, and intelligence gathering, the last of which is considered in the following study.

Organization of this Study

Despite the ongoing influence of nineteenth century romantic-nationalist models, it is clear that many early medieval rulers, including Charlemagne and his descendants throughout much of the Carolingian Empire, enjoyed considerable long-term military success.8 Ineluctably, this success was based upon the effective management of a wide range of resources that required a high level of sophistication. As specialists in other historical periods have made abundantly clear, an important element of these military resources throughout the history of western warfare has been the establishment of a capable apparatus for the acquisition of timely information regarding a broad spec- trum of topics.9 The focus in this essay is on the efforts by military leaders to acquire intelligence for both long-term and immediate use over the course of the ninth century, with particular respect to the Carolingians and their adversaries. By illuminating the extensive efforts of both the Carolingians and their opponents, including the Muslims in Spain, the Vikings, and the Slavs, to acquire and utilize militarily useful informa- tion in both the long and short term, we hope to develop a more realistic picture of the overall conduct of war during the ninth century and to help dispel the lingering cob- webs of nineteenth century nationalist historiographies perpetuated in the primitivist depiction of “barbarian” warfare. Mediaevistik 33 . 2020 91

The acquisition of intelligence can be divided somewhat arbitrarily into three main categories: strategic intelligence, campaign intelligence, and battlefield or tactical intelligence. Although the material considered in these categories necessarily over- lapped, strategic intelligence is concerned with developing information about both political and military interests that extend beyond a single campaigning season, and also relates to the development of a wide range of resources to plan for and meet long- term military needs. The discussion below regarding strategic intelligence, therefore, is divided into two parts treating, respectively, the acquisition of this intelligence, and its use in long-term military planning. Campaign intelligence considers matters that might impact the success of the campaign as a whole such as the overall physical and military topography of the region through which the army is to march, the evaluation of factors that would impinge upon the logistical support of the army, the overall scale and disposition of the enemy’s forces, and an evaluation of the resources that would be required to meet the campaign’s objectives. Battlefield or tactical intelligence was and is concerned primarily with information that might impact decision-making about the conduct of a particular military encounter such as the size and location of the enemy force as well as its composition and disposition. The historian of this period is particularly fortunate in the survival of a wide range of written sources that shed light on the conduct of war, generally, as well as the spe- cific question of the gathering of military intelligence and its use in developing both long and short term responses to threats and potential threats posed by adversaries. These include a substantial number of historiographical texts, many of which were written by men with either personal experience in the conduct of war, or with access to numerous informants who were experts in this topic. In addition to histories and annals, we have letters, handbooks, and prescriptive commands as well as the “work product” of intelligence gathering operations that also treat military matters. These written sources of information are complemented by an enormous, and continual- ly growing, corpus of material sources developed through excavations, which both corroborate information provided by written sources, and also shed light on military activities, such as the construction of numerous fortifications, that are not recorded in any surviving texts.

Strategic Intelligence

In the late eighth or early ninth century, Abbot Adalhard of Corbie (died 826), Charle- magne’s first cousin, composed a handbook regarding the administration of the royal court entitled De ordine Palatii, which included substantial information relating to the collection of military intelligence.10 The text of De ordine Palatii subsequently was reworked by Archbishop Hincmar of Rheims (845‒882) during the late 870s for the use of the royal court under the West Frankish ruler King Carloman II (879‒884). Notably, however, Hincmar did not choose to revise the sections of the text that dealt with military matters generally, and with intelligence gathering, specifically, which indicates the ongoing validity of Adalhard’s observations in the late ninth century.11 92 Mediaevistik 33 . 2020

In the context of this study, it would appear that Hincmar intended to validate Adal- hard’s contention that in a properly organized court, the ruler would seek information from throughout the realm and beyond its borders, and that this information should be used in the planning of military operations. The text of the De Ordine Palatii specifi- cally recommends that the king command each person summoned to court for whate- ver purpose to bring with him whatever information he could, which could be sifted for insights that possessed value in a military context. In particular, those individuals living on or near the frontier were to bring with them information regarding the situa- tion beyond the frontier.12 Among the most important pieces of information that were desiderata were signs of disturbances that might lead to rebellions by peoples within the kingdom.13 It was also very important, according to this handbook, to obtain in- formation about the intentions of subjected peoples (gens subdita) living outside the frontiers of the realm.14 Efforts also were to be made to develop information about the behavior of peoples beyond the frontier that had not yet been conquered.15 This focus on intelligence gathering, as discussed by Adalard and affirmed by Hin- cmar, permeates many of the written sources that survive from the later eighth and ninth centuries. We can see, for example, that the author of the epic Latin poem de- scribing the adventures of Waltharius, the so-called Walthariuslied in German, which was written around the turn of the ninth century, presents intelligence gathering by the Frankish king as intrinsic to the ruler’s duties. In the course of the poem, the Frankish ruler, called Gibicho, was served a fish for dinner that was not of a type typically found in the area. This fact, according to the author of the poem, made the ruler quite su- spicious. Consequently, the king summoned the head of the palace kitchen to find out where he had obtained this “foreign” fish. Gibicho observed that this fish was of a type not found in Francia, and must have come from beyond the frontier. In response, the cook explained that he had obtained the fish from a man who operated a ferry on the Rhine River near Worms where the court was meeting. The king then had the ferry- man summoned to court and personally questioned him about the fish and its origins. The ferryman explained that it was a very well-armed stranger, who had patronized the ferry, who had given him the fish. As a result, the ruler was able to determine that a foreigner had come into the realm and that this information had to be pursued. In sum, this episode from a literary work presents the gathering of information about odd or unusual events as a normal part of the routine of a Frankish ruler.16 It is noteworthy that the discussion of the “foreign” fish in the Waltharius poem is far from central to the work’s narrative arc, and serves largely to provide a context for the relationship among the main characters in the story. This kind of incidental detail was only effective if it met the expectations of the audience and did not alienate them by violating their sense of a plausible context.17 The emphasis on the gathering of information by the court, which we see in hand- book form in De Ordine Palatii, and in literary form in Waltharius has its counter- part in a surviving letter sent by Charlemagne in 807 to Bishop Ghärbald of Liège (784‒809).18 The ostensible purpose of Charlemagne’s letter was to inform Ghärbald that he, and all of his ecclesiastical confreres, were to organize a series of penitential rites across the kingdom in order to beg for God’s favor to end the bad fortune that had struck the realm. It is in this context that Charlemagne informs the bishop that Mediaevistik 33 . 2020 93

“we have learned through our faithful men, who have provided information to us from every part of our realm, that crops have failed to a far greater extent than is normal, and there is an imminent threat of famine.”19 Charlemagne added that he also had received word about the continuous efforts of the pagan peoples living beyond the frontiers to wage war against the Frankish kingdom, and added that there were many other difficulties that were too numerous set down in writing.20 Charlemagne’s mention in his letter to Bishop Ghärbald of the enormous range of sources of information available to him was essentially a throw-away line, but it does highlight this ruler’s keen appreciation of the need for all types of intelligence, and the utilization of this information to plan responses to current or potential dangers. One particularly important source of information, with a specifically military focus, addressed in De Ordine Palatii, consisted of men who had gained expertise in one or another operational theater along the frontiers of the Empire. These men are treated in the handbook’s discussion of the annual planning sessions undertaken by the court every winter to prepare for the next year’s military operations. According to the text of De Ordine Palatii, these sessions included not only senior royal advisors, who were responsible for advising the ruler on military policy generally, but also special advi- sors, that is specialists (praecipui consiliarii), who had developed specific expertise in one or another region.21 Among these specialist advisors, contemporary writers assigned a particularly important role to the commanders of the military forces that were stationed along the frontier. For example, in discussing the ongoing political and potentially military challenges from the Bulgarian kingdom in the winter of 825‒826, the author of the Annales regni Francorum (ARF) emphasized the role played by Counts Baldrich and Gerold, the commanders of the frontier with Bulgaria, in sifting through the divergent rumors and information regarding the assassination of the Bulgarian king. The ARF also mentions the report by these same counts to the imperial court in the summer of 826 regarding their assessment of the movement of Bulgarian troops, and their conclu- sion that there was no immediate threat along this frontier.22 The poet and one-time royal official Ermoldus Nigellus provides a similar example of the important role played by frontier military commanders in offering their exper- tise in his verse history of the Carolingian dynasty and biography of Louis the Pious composed in the mid‒820s. In discussing the imperial assembly held early in 818, for example, Ermoldus records that Louis the Pious summoned specific commanders to come from the frontier to make reports on their regions.23 Ermoldus mentioned parti- cularly the presence of Lambert, count of Nantes, who commanded the Breton fron- tier. It was on the basis of Lambert’s report, in Ermoldus’s telling, that Louis decided that war against the Bretons was necessary.24 Ermoldus provides an even more detailed discussion of the expertise provided to the court by frontier commanders in his account of the annual planning assembly held early in 801. In this case, Ermoldus describes Charlemagne as asking the commanders of his frontier forces for advice about where he should campaign that year.25 It is in this context that Dux William of Toulouse (790‒806) is presented as offering detailed intelligence to the court regarding the disposition of Muslim forces in Spain, based upon his own reconnaissance efforts. This information included a discussion of the 94 Mediaevistik 33 . 2020

Muslim fortifications, the location of their military forces, and the safest routes for entering their territory.26 In Ermoldus’s account, the information provided by William was exceptionally important in planning the campaigns that ultimately would lead to the capture of the fortress city of Barcelona in 802, a topic that is addressed again below.27 Ermoldus was seeking reinstatement at court following his banishment by Louis the Pious and hoped his epic poem would serve as the vehicle for his political redemp- tion. He had every interest in presenting both the ruler and his important advisors as following the best possible course of action in pursuit of their military objectives. Consequently, Ermoldus’s depiction of the efforts of a frontier commander such as the dux William to obtain militarily valuable intelligence almost certainly is one that the poet imagined would be well received at court. It is also clear that William’s actions were consistent with the advice set out in the handbook De ordine palatii, discussed above, to obtain reliable intelligence about adversaries across the frontier. Even more strikingly, Ermoldus’s discussion of the importance of obtaining intelligence regar- ding the enemy’s military assets also is consistent with an exceptional piece of survi- ving “work product” that was collected at the behest of Louis the German sometime between 846‒862.28 The eastern frontier of the East Frankish realm during Louis the German’s reign spanned almost a thousand kilometers from the fortress of Moosburg on the Isar River in the south to the mouth of the Elbe River in the north. The East Frankish king faced hostile or potentially hostile neighbors along almost the entirety of this frontier, and routinely dispatched armies into Moravia, and in the trans-Saale and trans-Elbe Slavic lands.29 It is in this context that Louis required a detailed account of the strongholds maintained by his enemies and potential adversaries. We are exceptionally fortunate to possess a single surviving manuscript that provides a detailed inventory of these fortresses. The document in question, which is sometimes referred to as the work of the Bavarian Geographer, bore the title of Descriptio civitatum et regionum septen- trionalem plagam Danubii (Description of the Fortresses and Regions North of the Danube) and treated the entire frontier from the North Sea to the Danube basin.30 The text provides a list of the number of fortresses possessed from north to south by the Obodrites, Wilzi, Hevelli, Sorbs, Daleminzi, Bohemians, and Moravians, with a total of 246 strongholds in all. Extensive archaeological research since the end of the Se- cond World War, particularly work that draws upon the techniques of dendrochrono- logy, has been successful in identifying large numbers of the strongholds listed in the Descriptio. Of particular importance, many of these fortifications can be dated from the early to mid-ninth century, which tends to confirm the information provided to the East Frankish court by the so‒called Bavarian Geographer.31 As a corollary to obtaining strictly military information about neighboring peoples, the Carolingian rulers also were concerned with developing political intelligence that would provide a basis for evaluating future military threats. The ARF describes an example of this type of political intelligence gathering in the context of the ongoing struggle for the Danish throne in 823. Harald, the king of Denmark (819‒827), came to the imperial court at Compiègne in the late autumn of this year to ask Louis the Pious for aid against the sons of one of his predecessors King Gudfred (804‒810). Mediaevistik 33 . 2020 95

Rather than immediately providing military aid, as Harald had requested, Louis ins- tead dispatched two counts, Theothari and Hruodmund, to meet with Gudfred’s sons and investigate the balance of political forces within Denmark and, as the author of the ARF put it, “all that they could find out in these lands.”32 In order to ensure that he received the most detailed possible account of the situation in Denmark, Louis also dispatched Archbishop Ebo of Rheims (died 841), ostensibly to preach in the Danish kingdom. However, there can be little doubt that Ebo also was engaged in intelligence gathering, particularly as he returned to the Frankish court in the company of Counts Theothari and Hruodmund.33 A similar example of political intelligence gathering is revealed in a fortuitously surviving letter sent by Margrave Aribo of the Pannonian frontier (871‒909) to King Arnulf of Carinthia (887‒899), a grandson of Louis the German.34The letter, which was written in a simple and grammatically challenged Latin, informed Arnulf that Aribo’s agents, here called missi, had returned from the East, and had brought him news about what was happening in the Slavic border lands of his March. In particular, Aribo reported that the Slavic people, whom he denotes as the Marahoni, which should be taken to mean the Moravians, were prepared to subordinate themselves to Arnulf’s rule, and to reject the rule of their current leader Svatopluk, who held power in Mo- ravia (ca. 870‒ca. 894).35 Aribo’s letter also makes clear that Bishop Wiching of Nitra (880‒891), who later served as Arnulf’s chancellor (892‒899) and as bishop of Passau (898‒899), also was operating in the Slavic lands and had obtained additional intel- ligence for the royal court.36 Hans Martin Schwarzmaier, who edited the letter from Aribo, concluded that both this margrave and Bishop Wiching served King Arnulf as experts on Slavic and eastern affairs for many years, and makes clear that this letter is simply a fortuitously surviving example of their intelligence gathering operations.37

Strategic Intelligence: Long Term Planning

The collection of intelligence about the military capabilities as well as the political intentions of their enemies by the Carolingians led, inter alia, to the development of long-term responses that extended beyond the planning for individual military cam- paigns. For example, Einhard, Charlemagne’s courtier who wrote his biography of the great ruler early in the reign of Emperor Louis the Pious (814‒840), emphasized that the emperor established an early warning system along the North Sea coast as part of a comprehensive plan to combat raids by the Vikings.38 In particular, Charlemagne commanded that every harbor that was large enough to admit a raiding ship was to be provided with a permanent watch that would be in position to mobilize the surroun- ding region to defend against a raid. This coast watch system also was to include every river mouth that was sufficiently large to admit enemy ships.39 The coastal watch system continued in use during the reign of Louis the Pious and its functioning is discussed by Einhard in a letter that he sent circa 832 to one of Louis the Pious’s missi.40 The purpose of this letter was to ensure that Einhard’s men would not be subject to the fine for failure to appear for military service heribannum( ) when 96 Mediaevistik 33 . 2020 summoned by the missus, because they already were doing their military duty along the coast. Einhard emphasizes in the letter that: “I thought that you already knew that our men, who are under our authority in these parts, have gone to guard the coast according to the command and order of the lord emperor, not only during the period when he set out for Tribur, but also when he arrived at Orléans.41 As a consequence, Einhard added, “it does not seem just to me that they should have to pay the fine for failing to perform military service when they were elsewhere unless the emperor, himself, commands it.”42 Even more systematic responses that drew upon the development of strategic in- telligence can be seen the construction of entire defensive systems to oppose ongoing military threats. In the early ninth-century, for example, Charlemagne established the Limes Saxoniae, consisting of a large number of fortresses, many located along the lower course of the Elbe River, which served to defend the Saxon region from attacks by the Danes, and later by the Slavic Obodrites.43 The first report of this defensive system appears in the ARF, which records that in 809, after learning about the “pride and arrogance” of the Danish king, Charlemagne decided that it would be prudent to take appropriate defensive military action to deter any attacks from this direction. Consequently, he commanded that a fortress be constructed on the east bank of the Elbe River, and provided a substantial garrison to defend this place.44 Charlemagne’s grandson Louis the German, the son of Louis the Pious, also esta- blished a military march comprising numerous fortifications located along the Saale River basin as part of his effort to control the Sorbs, who lived in the region between the Saale and Elbe Rivers.45 This militarized frontier began as an eastern offshoot of the Germar Mark, originally established by Charles Martel as a defense in depth against the Saxons, and was expanded under King Pippin and then Charlemagne to encompass the valley of the Unstrut River.46 Eventually the Sorbian March, in the form it achieved under Louis the German, provided the springboard for the conquest of the entire Sorbian region by King Henry I (919‒936), and its integration into the German kingdom.47 The opponents of the Carolingians similarly drew upon their extensive knowledge of Frankish military strategy and tactics to develop their own systems of defensive works along the frontier zones. Among the most famous of these is the Danevirk, which was greatly expanded and strengthened by the Danish ruler Gudfred, menti- oned above, in an effort to make more difficult a Carolingian invasion of his kingdom by land. This system of ditches, watchtowers, fortifications, and connecting roads ex- tended for more than 30 kilometers along the southern frontier of the Danish kingdom in Schleswig.48 Somewhat later in the ninth century, the Moravian opponents of Louis the Pious and subsequently of Louis the German as well constructed a system of mas- sive fortresses, which were intended to blunt the efforts of the Carolingians to impose a tributary status on Moravia, or even to conquer the region.49 Many of these fortres- ses have been excavated, and reveal an enormous investment of human and material resources.50 The construction of these systems of fortifications necessarily involved both long- term planning, based on the acquisition of strategic intelligence, and the considerable deployment of resources over a lengthy period. For the early medieval period, it is Mediaevistik 33 . 2020 97 sometimes possible to identify elements of the planning and implementation process on the basis of surviving written sources. For example, the author of the ARF reports, as discussed above, that Charlemagne constructed a fortress along the course of the Elbe River in 809, which became part of the larger Limes Saxoniae. In addition, Adam of Bremen, writing in the later eleventh century, described in some detail the course of the Limes Saxoniae, and likely drew this information from a now lost royal document, produced during the early ninth century.51 Taken together, these two texts provide an indication of the planning that went into the development of the entire system of forti- fications that protected the Saxon frontier. Indeed, the author of the ARF records that it was only after the location for the establishment of the fortress on the Elbe had been explored to determine whether the site was suitable that Charlemagne ordered its con- struction in 809. This more or less offhand remark by the author points to the extensive planning that was required for the establishment of just one of many strongholds that comprised the Limes Saxoniae.52 In other cases, however, there is much more limited written information regarding the planning that undergirded the construction of a particular fortress or the develop- ment of a system of fortifications. In these circumstances, the relatively new tradition of landscape archaeology, largely dominated at present by British specialists, provides useful models for “reading” the man-made and natural topography in the manner that other scholars read texts.53 Of particular importance in this new tradition has been the effort by specialists in Anglo-Saxon studies to attempt to read the human intention that directed the construction of individual fortifications as well as systems of fortresses. A primary focus has been on the overall defensive plan that can be deduced from the pla- cement of not only fortifications and roads, but also watch towers and signal stations that together comprised the military system that is described, in part, in the document now known as the Burghal Hidage. This administrative document, produced in the early 10th century, detailed the provision of garrisons for about 30 fortifications that defended the kingdom of Wessex from the Vikings.54 The concept developed by the practitioners of landscape archaeology is a powerful tool demonstrating how modern scholars can read the intentions of the military deci- sion makers through an analysis of the systems of mutually supporting fortifications with connecting roads. With respect to the Carolingians, the importance of this insight can be seen with respect to the fortresses that studded the Sorbian March, menti- oned above. In an analysis of the document known as the Hersfelder Zehntverzeich- nis (HZV), which described the tithe revenues that were granted by Charlemagne to the monastery of Hersfeld in 780, Walter Schlesinger identified 19 fortresses urbes( ), which were elements of a much larger military system that had been constructed ori- ginally by King Pippin I (751‒768) and then expanded by Charlemagne. The purpose of this system of fortresses was to defend the Frankish realm from attacks, at first from the Saxons, and later from the Slavs.55 Working on Schlesinger’s insights, the archaeologist Paul Grimm, in what might be considered a proto-landscape archaeological study, synthesized the available archaeo- logical, topographical, and onomastic studies to show that the system of fortifications listed in the HZV, which subsequently were maintained by Louis the Pious and Louis the German in the context of the Sorbian March, comprised a well thought out system 98 Mediaevistik 33 . 2020 of defense in depth.56 Grimm was able to identify two defense lines in the HZV, the first and earlier of these, along the Unstrut River, and the second along the Saale River. The seven fortifications along the Unstrut covered a front of about 27 kilometers, leaving fewer than 5 kilometers between each stronghold. This Unstrut line connected along its westernmost end to the long-established Germar Mark, mentioned above. The nine fortresses along the Saale River covered a front of about 50 kilometers, with an avera- ge distance among them of just over six kilometers.57 These two lines of fortifications, and their connected road system offered a system of defense against attacks from eit- her the north or the east against the densely populated and rich lands of Thuringia. The Carolingian rulers constructed similar fortified marches along other frontiers of their kingdom. During the later eighth century, for example, Charlemagne estab- lished a military administrative zone running from Aquitaine to the foothills of the Pyrenees under the command of Count Chorso of Toulouse, a predecessor of Dux William, discussed above. Chorso was given responsibility for establishing several military colonies along the frontier, whose members were required to maintain and defend a group of established and new strongholds to deter or limit Muslim aggression to the north.58 King Charles the Bald (840‒877), the son of Louis the Pious, similarly developed a long-term military response to the ongoing threat of Viking raids by con- structing a number of fortified bridges over the rivers that fed into the North Sea and the English Channel. The purpose of these fortifications was to interdict Viking fleets and prevent them from rowing upstream to attack targets in the interior of the king- dom.59 Taken together, the costs for constructing the strongholds along these frontiers, and subsequently the costs for maintaining and garrisoning them were very high.60 Such extensive endeavors certainly were not undertaken without significant planning, which was based upon the acquisition of strategic intelligence.

Campaign Intelligence

The emphasis in the handbook De Ordine Palatii on the importance of planning ses- sions every winter, with information gathered from men who had developed expertise in many different regions of the empire, illuminates the important connection between strategic intelligence and individual military campaigns. Much of the intelligence that was gathered for the purpose of developing long-term plans, of the types considered in the previous section, also was of value in the context of developing strategies for a par- ticular campaign. Ermoldus’s discussion of the intelligence gathered by Dux William, considered above, makes clear that it was this commander’s detailed information about Muslim fortresses and the road system in the region around Barcelona that facilitated the conquest of this fortress city after two years of campaigning with three armies in the field as well as a fleet.61 In other cases, the acquisition of intelligence regarding the actions or plans of ene- mies beyond the frontiers led to more immediate action by Carolingian rulers. For example, in 808, according to the author of the ARF, Charlemagne dispatched an army comprised of both Frankish and Saxon contingents under the command of his son Mediaevistik 33 . 2020 99

Charles to the Elbe frontier in response to news that the Danish king Gudfred had be- gun a military operation against the Obodrites, a Slavic people whose homeland was located east of the Elbe River, when they were allied with Charlemagne.62 Louis the Pious’s biographer, the so-called Astronomer, also comments on the value of intelligence regarding foreign powers in developing military plans for specific cam- paigns. The Astronomer reports, for example, that when Louis the Pious arrived at the town of Thionville, located on the left bank of the Mosel River, in the summer of 829, he received reports that the Muslim rulers in Spain were planning a substantial mili- tary action across the frontier. In response, Louis commanded his eldest son Lothair to lead a strong army to Lyon and there to wait for additional forces under the command of his second son Pippin to join him with troops mobilized from Aquitaine.63 When the two brothers joined their forces, they received additional intelligence, according to the Astronomer, that the Muslims had, indeed, mobilized a large army, but were no longer advancing toward the frontier.64 One might postulate that the Muslim comman- ders had their own sources of campaign intelligence, and that having learned about the mobilization of a large Frankish army they decided to alter their plans. Contemporary chroniclers also depict Louis the Pious’s sons as drawing upon mi- litary intelligence to help them prepare appropriately for campaigns. For example, Nithard, a grandson of Charlemagne and a high-ranking official in the governments of both Louis the Pious and his son King Charles the Bald (840‒877), explains that follo- wing Louis the Pious’s death in June 840, his eldest son Lothair intentionally advanced at a very deliberate pace (pedetemptim) northward from his kingdom in Italy because he wished to know the political and military situation in the Frankish kingdom before he crossed the Alps. 65 In a rather different context, Archbishop Hincmar of Rheims, mentioned above, recorded in the Annals of St. Bertin that King Louis the German was able to forestall a rebellion in what is today Slovenia by deploying large military forces there on the basis of information that he acquired about the would be rebels’ plans.66 Rudolf, the initial author of the Annals of Fulda, similarly records the efforts of Louis the German to obtain intelligence about his opponents, both those to the West and those to the East as part of his ongoing military operations. In discussing the critical situation of the year 858, in which Louis the German invaded the kingdom of his brother Charles the Bald at the invitation of a number of West Frankish magnates, Rudolf describes Louis’s efforts to ascertain Charles’s plans by dispatching spies to his court.67 The East Frankish king sent Count Conrad of Auxerre and the latter’s brother Hugh to King Charles in the expectation that they would be received there because their sister Judith was Charles’s mother. However, rather than spying on Charles for Louis, the two men switched their allegiance and gave a full report to the West Fran- kish king about the military and political position of Louis. As a consequence, Charles was able to outmaneuver his elder brother, and force him out of the West Frankish realm.68 Louis the German’s efforts to obtain intelligence about his opponents were rather more successful in the East in 858, where his agents in the Sorbian region, to the east of the Saale River, brought word that the royal fidelis Dux Zistibor had been assassi- nated. Moreover, Louis learned that the assassins and their supporters were planning to lead the Sorbs in revolt against their Frankish overlords.69 As a consequence of the 100 Mediaevistik 33 . 2020 rapid receipt of this news, Louis the German was in a position to take action against the would-be rebels and dispatched an army under the leadership of Thachulf, the commander of the Sorbian March, to prevent any uprisings.70 In a similar vein, Megin- hard, who took over composition of the Annals of Fulda after 863, reports that in 871, Louis the German dispatched forces under the command of Bishop Arn of Würzburg (855‒892) and Count Ruodolt of Nordgau to defend the frontier in Bavaria because the court had received information that the Bohemians were planning an invasion.71 It is clear that the Carolingian authors were aware that their opponents also sought information that would help them to prepare for campaigns. According to Meginhard, for example, the Bohemians and Sorbs were able to gather information about the defeat and destruction of a Saxon army under the command of Count Brun by the Vikings in 880. As a consequence, the Bohemian and Sorb leadership decided that they would take advantage of what they assumed would be significant confusion in the East Fran- kish realm by launching a major attack on those Slavic peoples living along the Saale River who were loyal to the Franks.72 However, before the Bohemians and Sorbs could launch their invasion, Poppo, who held office as dux of Thuringia and commander of the Sorbian march (880‒892), struck first and invaded the territory of the Daleminzi, one group among the Sorbian confederation, and won a significant victory.73 It would appear that Poppo was just as well informed about events across the Saale frontier as were his Slavic opponents about events in Saxony. In addition to developing information about their adversaries, the Carolingian ru- lers also are reported in contemporary sources to have engaged in a rigorous process of self-evaluation following campaigns in order to ascertain what had gone well, and par- ticularly what errors had been made. The author of the ARF, for example, records that in 827 Louis the Pious dispatched two separate columns, one under the command of his chancellor Helisacher and Counts Hildebrand and Donatus, and a second under his son Pippin to put down a revolt in the Spanish March, and also to deal with incursions by the Muslims, who were providing support to the rebels against Carolingian rule.74 Unfortunately for the inhabitants of the Spanish March, Frankish troops did not arrive in time to prevent the Muslim forces from crossing the border and ravaging the region around Barcelona and Gerona. The author of the ARF commented that the tardiness of the Carolingian army was due to the negligence (desidia) of the commanders whom Louis the Pious had appointed.75 As a consequence of this failure, Louis the Pious commanded that a thorough inves- tigation be made regarding the events leading up to the successful Muslim raids in the Spanish March. The results of this investigation were presented to the imperial court that was held at Aachen in February 828.76 In fact, the author of the ARF emphasized that the events that took place in the Spanish March were given particular attention at this assembly, and as a result of the investigation, the leaders of the army that had arrived too late to prevent Muslim incursions were found guilty of negligence and removed from office.77 In addition to dealing with the military failures in the Spanish March, the court at Aachen also undertook an investigation of the reasons by why the frontier defenses in the March of Friuli in Northern Italy had failed to prevent a des- tructive raid by the Bulgarians. As a result of this second investigation, according to Mediaevistik 33 . 2020 101 the ARF, the dux of the March of Friuli, Baldrich, also was removed from office. His duties subsequently were divided among four counts.78

Battlefield and Tactical Intelligence

As contemporary observers were well aware, once military forces were in the field, obtaining intelligence about the opponent’s numbers, position, and plans was essential to achieve success and avoid defeat. In this context, narrative sources from the ninth century provide important information about active intelligence gathering both by the Carolingians and their adversaries. For example, the so-called Astronomer described the actions of the Muslims in Spain to detect the movements of a Carolingian army tas- ked in the summer of 808 with the goal of ravaging the region around the strategically important city of Tortosa, located approximately 180 kilometers southwest of Barcelo- na.79 The Carolingian army, under the command of the royal missus Ingobert, sought to disguise its crossing of the frontier along the Ebro by bringing along prefabricated ships, which could be carried in sections and then assembled when the army reached an unguarded section of the river.80 The Carolingian forces successfully executed this plan; however, according to the Astronomer, some horse dung from this column floated down river and was seen by a Muslim soldier. This man is reported to have recognized that the barley in the dung likely came from military mounts rather than a wild ass or other grass-fed animal, and hurried with this information to his superior. Alerted by this telltale sign of foreign military forces in the vicinity, the local Muslim commander then dispatched scouts, who were able to locate the Carolingian troops. This information subsequently was passed along to the garrison commander at Tortosa, who put the city’s defenses into order and withstood the subsequent siege.81 Whether this account, which on its face sounds rather fanciful, represents an actual event or is rather an example of realistic verisimilitude is less important in the present context than is the expectation of the Astronomer that his audience would accept without demur that the Muslims routinely used scouts to keep track of enemy forces in the field.82 Indeed, it was not only the Muslims who can be seen in ninth century sources using scouts. The Vikings also are depicted by contemporary Frankish writers as deplo- ying scouts to gain tactical information about their Carolingian opponents. Notker the Stammerer (died 912), who wrote his Deeds of Charlemagne during the reign of Emperor Charles III (881‒887), recorded in passing that scouts (exploratores) of the Northmen pirates were operating by ship in the area around Narbonne.83 The real import of the story, for Notker, was not that the Vikings used scouts. This was merely part of the context for this anecdote, which, from a rhetorical perspective, permits the inference that Viking scouts were well-known to Notker’s likely audience. Rather, Notker used the presence of these Viking scouts to highlight Charlemagne’s perspi- cacity in being able to identify the ships as belonging to the enemy although many of his courtiers thought that the ships might belong to Jewish, Breton, or even African merchants.84 102 Mediaevistik 33 . 2020

Regino of Prüm, Notker’s near contemporary, also commented on the use of scouts by the Vikings, albeit for operations on land rather than on the sea. According to Regi- no, a large Viking army sailed up the Mosel River in the spring of 891 and landed near Liège, thereby avoiding the forces deployed along the bank of this river by King Ar- nulf of Carinthia (887‒899).85 Once they had eluded the main force of Arnulf’s army, the Vikings dispersed to gather supplies, causing considerable damage to the local inhabitants as well as capturing trains of supply wagons dispatched by the Carolingian ruler to provision the Frankish troops in the field. After receiving reports of the Viking activities from their own scouts, the Frankish commanders consolidated their forces on the morning of 25 June. They then decided to dispatch a reconnaissance in force, comprised of picked troops, to locate the Northmen. However, according to Regino, at the same time that the Frankish commanders were making this plan, Viking scouts (speculatores) suddenly appeared. Unfortunately for the Franks, the commanders lost control over their forces at this point, and their men charged headlong after the Viking scouts, who led them directly into the mass of the Viking army located near the Geule River, where the Franks were defeated soundly.86 As Regino’s discussion of the battle of Geule makes clear, the use of scouts to gain tactical information was just as familiar to the Carolingians as it was to their opponents. In fact, many contemporary writers commented either directly on the deployment of scouts by Frankish military commanders, or discussed the battlefield actions that they took, which were dependent upon the obtaining of important tactical information. The Annals of St. Vaast, for example, reports that in August 881 King Louis III of West Francia (879‒882), the elder brother of King Carloman, was pursuing a force of Vik- ings, which he believed was heading toward the town of Lavier along the Somme Ri- ver.87 In order to make sure of Vikings’ whereabouts and avoid being ambushed, Louis dispatched exploratores, who brought back word that the Northmen were heavily bur- dened with booty. After receiving this information, Carolingian ruler commanded his troops to increase their pace and, as a result, was able to block the path of the Vikings at a villa called Saucourt, near Abbeville, and forced them to fight a battle there. The result, according to the author of the Annals, was a significant victory for Louis III’s army. 88 The Annals of St. Vaast also discuss the efforts Henry dux of the Austrasians, one of Emperor Charles III’s leading military commanders, to gain information about Viking forces that were besieging Paris in 886.89 In this case, rather than sending out scouts, Henry actually led a reconnaissance himself, bringing only a few men with him. Ac- cording to the author of the Annales, Henry was hoping to learn of any weaknesses in the Danish position so that he could plan an attack against them.90 Unfortunately for Henry his horse fell into a ditch, which the Northmen had dug to protect their encampments, and he was killed by the Vikings.91 On a happier note for the Franks, Meginhard records in the Annals of Fulda that the East Frankish ruler King Arnulf (887‒899) carefully reconnoitered the Viking position before developing a successful plan to assault their position at the battle of the Dyle in 891.92 In other cases, contemporary authors report on the success of Carolingian comman- ders in obtaining sufficient tactical information about their opponents to ambush them, without specifically commenting on the use of scouts. For example, Nithard, discussed Mediaevistik 33 . 2020 103 above, provides considerable information about the ability of both Charles the Bald and his brother Lothair I (840‒854) to track the movement of each other’s forces in the spring of 841 in the midst of the great civil war following Louis the Pious’s death in 840. In this context, Nithard, who was one of Charles’s military commanders at the time, explains that as reinforcements were rushing to join Charles at the royal monas- tery of St. Denis, word arrived that Lothair’s troops were planning to ambush them. In response to receiving this information, Charles led his men on a forced march of approximately 100 kilometers to Saint-Mammés to join with his reinforcements and forestall this attack.93 According to Nithard, Charles then led his now united army on yet another forced march of 70 kilometers to the forest of the Othe, just east of Sens, to attempt a surprise attack of his own on Lothair’s troops, who were stationed there.94 However, this time the tables were turned, and Lothair’s men learned of the advance of Charles’s army, and made their escape. Nithard emphasizes that Charles was not able to engage in a close pursuit because the horses of his men were exhausted from the hard pace of the previous days.95 As the failures by both Lothair and Charles to ambush each other’s forces makes clear, successful operations required not only obtaining information about the enemy but also keeping one’s own position and plans secret. This need to keep one’s plans secret, or as we would say in the modern context, to maintain operational security, was addressed in De Ordine Palatii. In both the original version under Adalhard and in the revised text by Hincmar, this handbook stressed that military plans that had been approved by the king were to be kept secret, i.e. sub silentio. The text states explicitly that failing to keep plans secret might lead to a situation in which “persons, who, because of the information [they obtained] might wish to stop or undermine” the military effort, but when secrecy was maintained, opponents would not be able to do this.96 The failure to maintain this operational secrecy could lead, as in the examples discussed by Nithard, to frustration. In other cases, however, the failure to keep plans secret led to disaster. We can see a clear example of this problem in Meginhard’s description in the An- nals of Fulda of the battle of Andernach fought on 8 October 876 between armies under the command of Charles the Bald and his nephew King Louis the Younger (876‒ 882), the son of Louis the German.97 According to Meginhard, the gist of whose account is confirmed by Hincmar of Rheims in the Annals of St. Bertin, following the death of Louis the German, the West Frankish ruler Charles decided that he would attempt to conquer the region of the middle and lower Rhineland, which belonged to the kingdom of his nephew Louis the Younger.98 Charles, who sought in the traditional manner of Carolingian kings to lure Louis the Younger’s main supporters over to his own side with promises of offices and wealth, could not hide the fact that he had ente- red the Rhineland with a large army. To give himself some tactical flexibility, however, Charles continued to exchange messengers with Louis promising, as both Meginhard and Hincmar report, to seek a peace agreement that would be agreeable to both of them. But, as Meginhard emphasizes, Charles had no intention of making peace and instead began a forced march by night from the environs of Cologne toward Ander- nach, located approximately 80 kilometers to the south, where Louis was encamped, intending to launch a surprise attack and either kill or blind his nephew.99 104 Mediaevistik 33 . 2020

Unfortunately for Charles, Archbishop Willibert of Cologne (870‒889) was horri- fied by the actions of the West Frankish ruler, and sent one of his priests to warn Louis. This priest, named Hartwig, was able to follow a shorter route than the army, accor- ding to Meginhard, and was able to reach Louis the Younger while the West Frankish forces were still on the road. Consequently, Louis had the opportunity to prepare and set an ambush for Charles’s army. After receiving reports from his own scouts that Charles was nearby, the East Frankish king deployed a contingent of men on foot in front of his camp, which were to serve as bait for the western forces. Louis then de- ployed his mounted troops in the woods to either side of the clearing where his camp was located. Louis planned to use these mounted forces along the wings to undertake a double envelopment of Charles’s army as the West Frankish troops pursued Louis’s men, who were withdrawing slowly toward their camp. As Meginhard explains, the surprise was total, and Louis’s men achieved a significant victory when the attacks on the flanks of Charles’s army led to confusion, panic, and then a rout.100

Conclusion

Ultimately, rulers and military commanders at all levels in the ninth century required good information in order to make sound decisions whether planning the investment of extensive resources in the construction of a system of fortresses, organizing mili- tary forces and supplies for a single campaign, or operating against the enemy in the context of a single battle. This basic reality did not escape contemporary observers of warfare, including those who had personal experience in the conduct of war, such as Nithard and Ermoldus, or those who had access to detailed reports from military ex- perts, as was the case for Archbishop Hincmar of Rheims. What is striking about the surviving information from the ninth century is the manner in which written sources from a variety of genres and types, including not only historiographical texts, but also handbooks, letters, and reports, as well as material sources of information developed through excavations, tell the same story. Information and planning played key roles in military planning and operations during this ninth century, just as they did in other eras in western warfare. We hope that this brief discussion will lead the way to a more nuanced approach to warfare in the period after the death of Charlemagne, with stu- dies of matters such as logistics, military technology, and the training of fighting men, that will dispel even further the primitivizing perspective that all too often continues to bedevil treatments of the early Middle Ages. David S. Bachrach Dept. of History, University of New Hampshire 20 Academic Way, Durham, NH 03824 [email protected] Bernard S. Bachrach Dept. of History, University of Minnesota 1110 Heller Hall 271 19th Ave S., Minneapolis, MN 55455 [email protected] Mediaevistik 33 . 2020 105

Endnotes

1 With respect to the collection of military intelligence in the ancient world and late anti- quity, see Francis Dvornik, Origins of Intelligence Services. New Brunswick, NJ: Rutgers University Press, 1974, 3‒120. For the specific treatment of the Romans, see Wilhelm Blum, Curiosi und Regendarii. Munich: University of Munich, 1969); A. D. Lee, Informa- tion and Frontiers: Roman Foreign Relations in Late Antiquity. Cambridge: Cambridge University Press, 1993; Pamela Long and Alex Roland, “Military Secrecy in Antiquity and Early Medieval Europe: A Critical Reassessment,” History and Technology 11 (1994): 259‒90; and N. J. E. Austin and N. B. Rankov, Exploratio: Military and Political Intelli- gence in the Roman World from the Second Punic War to the Battle of Adrianople. London: Routledge, 1995. For Byzantine approaches to military intelligence, see Nike Koutrakou, “Diplomacy and Espionage: Their Role in Byzantine Foreign Relations: 8th‒10th Cen- turies,” Graeca-Arabica 6 (1995): 125‒44. Regarding the collection of military intelli- gence in the late medieval and early modern periods see, for example, John R. Alban and Christopher Allmand, “Spies and Spying in the Fourteenth Century,” War, Literature and Politics in the Late Middle Ages: Essays in Honour of G. W. Coopland, ed. Christopher Allmand. Liverpool: Liverpool University Press, 1976, 73‒101; Reuven Amitai, “Mamluk Espionage Among the Mongols and Franks,” Asian and African Studies 22 (1988): 173‒81; and Christopher Allmand, “Intelligence in the Hundred Years War,” Go Spy the Land: Military Intelligence in History, ed. Keith Neilson and B. J. C. McKercher. Westport, CT: Praeger, 1992, 31‒47. 2 For Norman and Anglo-Norman warfare see John O. Prestwich, “Military Intelligence under the Norman and Angevin Kings,” Law and Government in Medieval England and Normandy: Essays in Honour of Sir. James Holt, ed. George Garnett and John Hudson. Cambridge: Cambridge University Press, 1994,1‒30. The recent publication by Susan Edgington, “Espionage and Military Intelligence During the First Crusade,” Crusading Warfare in the Middle Ages: Realities and Representations, Essays in Honour of John France, ed. Simon John and Nicholas Morton. Aldershot: Ashgate, 2014, 74‒85, also has illuminated important aspects of the gathering of tactical military intelligence during the late eleventh century. Concerning the gathering of military intelligence in Ottonian and Salian warfare, see Bruno Scherff,Studien zum Heer der Ottonen und der ersten Salier (919‒1056). Bonn: University of Bonn, 1985, 124, 127, and 234, who discusses the import- ant role that scouts played in contemporary battlefield; and David S. Bachrach, “Military Intelligence and Strategic Planning under the Ottonian Kings of Germany, c. 919‒c.1024,” Military Cultures and Martial Enterprises in the Middle Ages: Essays in Honor of Richard P. Abels, ed. John Hosler. Woodbridge: Boydell Press, 2020, 61‒87. 3 For Charlemagne’s reign, itself, see Bernard S. Bachrach, “Charlemagne and the Caro- lingian General Staff,” The Journal of Military History 66 (2002): 313‒57; and id., “Adal- hard’s De ordine palatii: Some Methodological Observations Regarding Chapters 29‒36,” Cithara 39 (2001): 3‒36. 4 The literature dealing with the military history of Charlemagne’s reign is far too vast to treat here. For some guides to the scholarship, see Bernard S. Bachrach, “Charlemag- ne’s Early Campaigns (768‒777): A Diplomatic and Military Analysis. Leiden: Brill Press, 2013; Étienne Renard, “La politique militaire de Charlemagne et la paysannerie franque,” Francia 36 (2009): 1‒33; John France, “The Composition and Raising of Armies of Char- lemagne,” Journal of Medieval Military History 1 (2002): 61‒82; and Timothy Reuter, “The Recruitment of Armies in the Early Middle Ages: What Can We Know?” Military Aspects of Scandinavian Society in European Perspective, AD 1‒1300, ed. Anne Norgard Jorgensen and Birthe L. Clausen. Copenhagen: National Museum Press, 1997, 32‒37. 106 Mediaevistik 33 . 2020

5 Eric Goldberg, Struggle For Empire: Kingship and Conflict Under Louis the German, 816‒876. Ithaca, NY: Cornell University Press, 2006, does address certain aspects of Louis the German’s military organization, and Janet Nelson, Charles the Bald. London: Longman, 1992), also considers some aspects of Charles the Bald’s military organization. However, neither ventures any observations regarding the problem of military intelligence. From a longer durée perspective, the work by Andrea Stieldorf, Marken und Markgra- fen: Studien zur Grenzsicherung durch die fränkisch-deutschen Herrscher. Monumenta Germaniae historica, Schriften, 64. Munich: Monumenta Germaniae Historica, 2012, is of considerable value in demonstrating the task of early medieval rulers to defend the frontiers of their realms, but provides much less information about how this task was ac- complished. Simon Coupland’s unpublished dissertation Charles the Bald and the Defence of the West Frankish Kingdom against the Viking Invasions, 840‒877. Cambridge: Cam- bridge University Press, 1987, addresses some aspects of this ruler’s military organiza- tion but does not provide treatment of military intelligence. The same is true of Carroll M. Gillmor’s unpublished dissertation, Warfare and the Military under Charles the Bald, 840‒877. Los Angeles, CA: University of California at Los Angeles, 1976. 6 There are some limited exceptions to this otherwise barren landscape, particularly with re- gard to the struggle against the Vikings, Magyars, and Slavs. See, for example, Charles R. Bowlus, Franks, Moravians, and Magyars: The Struggle for the Middle Danube, 788‒907. Philadelphia, PA: University of Pennsylvania Press, 1995; Goldberg, Struggle for Empire (see note 5), 119‒46; Simon Coupland, “The Carolingian Army and the Struggle Against the Vikings,” Viator 35 (2004): 49‒70; and Ekkehard Eickhoff, “Maritime Defence of the Carolingian Empire,” Vikings on the Rhine: Recent Research on Early Medieval Relations between the Rhinelands and Scandinavia, ed. Rudolf Simek and Ulrike Engel. Vienna: Fassbaender, 2004, 50‒64. Also see the valuable study regarding military recruitment by Carroll Gillmor, “Charles the Bald and the Small Free Farmers, 862‒869,” Military Aspects of Scandinavian Society, 38‒47. None of these studies, however, address in detail the question of military intelligence. 7 Regarding this tradition, and its distorting effect on the reading of contemporary sources, with a focus on contemporary Anglo-Saxon England, see John D. Niles, “The Myth of the Feud in Anglo-Saxon England,” Journal of English and Germanic Philology 114.2 (2015): 163‒200. The use of terms such as warrior, war band, and war trail represent the dead hand of the romantic-nationalist historiographies of the nineteenth century. See, for example, Matthew Innes, “What Was Charlemagne’s Government,” Charlemagne: Empi- re and Society, ed. Joanna Story. Manchester: Manchester University Press, 2005): 71‒89, here 74; and Marios Costambeys, Matthew Innes, and Simon MacLean, The Carolingian World. Cambridge: Cambridge University Press, 2011, 159. Particularly influential in per- petuating the nineteenth-century historiographical tropes have been Timothy Reuter and Guy Halsall. See, in this context, Timothy Reuter, “Plunder and Tribute in the Carolingian Empire,” Transactions of the royal Historical Society, 5 ser. 35 (1985): 75‒94; “The End of Carolingian Military Expansion, Charlemagne’s Heir: New Perspectives on the Reign of Louis the Pious. 814‒840), ed. Peter Godman and Roger Collins. Oxford: Oxford Univer- sity Press, 1990, 391‒405; and “Carolingian and Ottonian Warfare,” Medieval Warfare: A History, ed. Maurice Keen. Oxford: Oxford University Press, 1999, 13‒35; and Guy Hal- sall, Warfare and Society in the Barbarian West, 450‒900. London: Routledge, 2003. 8 This point has been made, inter alia, by Nelson, Charles the Bald; Bowlus, Franks, Mora- vians, and Magyars (see note 6); and Simon MacLean, Kingship and Politics in the Late Ninth Century: Charles the Fat and the End of the Carolingian Empire. Cambridge: Cam- bridge University Press, 2003, despite his tendency to echo the primitivist model espoused by Reuter and Halsall with regard to military matters. Mediaevistik 33 . 2020 107

9 See the discussion of the differing types and scope of military intelligence in Bernard S. Bachrach and David S. Bachrach, Warfare in Medieval Europe c. 400‒c. 1453. London: Routledge, 2017, particularly 337‒55. 10 Regarding Adalhard’s authorship of this text, see Bachrach, “Charlemagne’s General Staff” (see note 3), 315‒17, and the literature cited there. The basic editions of De ordine palatii are Hincmarus de ordine Palatii, ed. and trans. Thomas Gross and Rudolf Schieffer in Monumenta Germaniae Historica. Fontes Iuris germanici antique in usum Scholarum separatim editi. Hanover: Monumenta Germaniae Historica, 1980; and Hincmar, De Or- dine Palatii, ed. and trans. Maurice Prou. Paris: F. Vieweg, 1884. 11 The scope of Hincmar’s revisions of Adalhard’s now lost text have been the subject of intense scholarly debate. See the synthesis of this discussion by Bernard S. Bachrach, “Adalhard of Corbie’s De ordine palatii: Some Methodological Observations Regarding Chapters 29‒36,” Cithara 41 (2001): 3‒34. 12 De ordine palatii (see note 10), ch. 36, particularly lines 619‒34. 13 De ordine palatii (see note 10), ch. 36, lines 626‒30. 14 De ordine palatii (see note 10), ch. 36, lines 630‒31. 15 De ordine palatii (see note 10), ch. 36, lines 632‒34. 16 Waltharius, ed. Karl Strecker, with a German translation by Peter Vossen. Berlin: Weid- mann, 1947, lines 428‒63. 17 The importance of providing a realistic frame or narrative arc in order to convince the audience of one’s main point is emphasized with respect to Carolingian sources by Thomas Scharff,Die Kämpfe der Herrscher und der Heiligen: Krieg und historische Erinnerung in der Karolingerzeit. Darmstadt: Wissenschaftliche Buchgesellschaft, 2002, 42. 18 Capitularia regnum Francorum, 2 vols., ed. Alfred Boretius and Viktor Krause. Monu- menta Germaniae Historica: Legum Sectio II. Hanover: Monumenta Germaniae Histori- ca, 1883, 1897, I: no. 124. 19 Capitularia I (see note 18), no.124: “conpertum habemus per fideles nostros, qui nobis de singulis regni nostri partibus haec nuntiaverunt, quod insolito more et ultra consuetum ubique terrae sterelitas esse et famis periculum imminere videtur.” 20 Capitularia I (see note 18), no. 124: On Charlemagne’s voracious appetite for information, now also see Jennifer Davis, Charlemagne’s Practice of Empire. Cambridge: Cambridge University Press 2017, 293‒336. 21 See De ordine palatii (see note 10), ch. 30, line 480, and the discussion by Bachrach, “Ge- neral Staff” (see note 3), 324‒26, who illuminates the ways in which the text produced by Adalard in the late eighth century can be used to show the work of military planners at Charlemagne’s court. 22 Annales regni Francorum (ARF), ed. F. Kurze MGH Scriptores Rerum Germanicarum, 6. Hanover: Monumenta Germaniae Historica, 1907, anno 826, p. 170. 23 Ermoldus Nigellus, In honorem Hludowici, ed. Ernst Dümmler. MGH Poetae Latini aevi Carolini, 2. Berlin: Monumenta Germaniae Historica, 1884, book 3, lines 5‒13 24 This is the gravamen of the entirety of book three of In honorem Hludowici (see note 23). See, in this context, the discussion by Julia Smith, Province and Empire: Brittany and the Carolingians. Cambridge: Cambridge University Press, 1992, 77‒79, with respect to Count Lambert’s role as frontier commander, and (63‒4) with respect to Ermoldus’s hosti- lity to the Bretons. 25 Ermoldus Nigellus, In honorem Hludowici (see note 23), book 1, lines 137‒57. 26 Ermoldus Nigellus, In honorem Hludowici (see note 23), book 1, lines 149‒50. 27 The preparations for the campaign against Barcelona and the capture of this city are the focus of the remainder of book 1. 108 Mediaevistik 33 . 2020

28 For a discussion of the range of possible dates for the production of this text, see Goldberg, Struggle for Empire (see note 5), 135‒37 29 See, for example, the discussion by Eric Goldberg, “Ludwig der Deutsche und Mähren. Eine Studie zu karolingischen Grenzekriegen im Osten,” Ludwig der Deutsche und sei- ne Zeit, ed. Wilfried Hartmann. Darmstadt: Wissenschaftliche Buchgesellschaft, 2004, 67‒94; and Bowlus, Franks, Moravians, and Magyars (see note 6), passim. 30 The report survives in one copy, Munich Clm 560, fols. 149v‒150r. 31 See, for example, Torsten Kempke, “Bemerkungen zur Delvenau-Stockitz-Route im frü- hen Mittelalter,” Hammaburg 9 (1989): 175‒84, here 176, who observes that at least 35 of the 53 Obodrite fortifications identified in theDescriptio have been excavated by archaeo- logists and dated to the early Slavic period corresponding to the ninth century. 32 ARF, anno 823 (see note 22), p. 162 “et imperatori omnia, quae in illis partibus comperire potuerunt, patefecerunt.” 33 ARF (see note 22), 162. 34 The late ninth century letter was preserved in the binding of a fifteenth century codex produced at the monastery of Reichenau in the manuscript Aug. Perg. CCXLVIII. For a detailed study of this text, its transmission, and content, see Hans Martin Scharzmai- er, “Ein Brief des Markgrafen Aribo an König Arnulf über die Verhältnisse in Mähren,” Frühmittelalterliche Studien 6 (1972): 55‒66. 35 For an analysis of the content of this letter, see Scharzmaier, “Ein Brief” (see note 34), 60‒63, and for the text, itself, see 57. 36 Scharzmaier, “Ein Brief” (see note 34), 60. 37 Scharzmaier, “Ein Brief” (see note 34), 60‒01. 38 Einhard, Vita Karoli Magni, ed. O. Holder-Egger. MGH Scriptores Rerum Germanicarum, 25. Hanover: Monumenta Germaniae Historica, 1911, ch. 18. 39 Einhard, Vita Karoli Magni (see note 38), ch. 18. 40 Epistolae karolini aevi, vol. 3, ed. Ernst Dümmler. Berlin: Monumenta Germaniae Histo- rica, 1899, no. 23 p. 121. 41 Epistolae, no. 23 (see note 40), p. 121, “Putabam tibi bene cognitum esse, quod homines nostri, quos in istis partibus habemus, secundum ordinationem et iussionem domni impe- ratoris ad custodiam maritam fuerunt, non solum eo tempore quando ille [ad] … oriam profectus est, sed etiam quando Aurelianos perrexit.” 42 Epistolae, no. 23 (see note 40), p. 121, “Et ideo non videtur mihi iustum esse, ut heriba- nnum solvere debeant, qui non aliubi fuerunt, nisi ubi ipse imperator precepit.” See the discussion by Eikhoff, “Maritime Defense” (see note 6), 51‒54. 43 The Limes Saxoniae has been the subject of considerable scholarly attention by both his- torians and archaeologists. See, for example, the synthesis by Matthias Hardt, “Linien und Säume. Zonen und Räume an der Ostgrenze des Reiches im frühen und hohen Mittelalter,” Grenze und Differenz im frühen Mittelalter, ed. Walter Pohl and Helmut Reimitz. Vienna: Verlag der Österreichischen Akademie der Wissenschaften, 2000, 39‒56; and id., Hesse, Elbe, Saale and the Frontiers of the Carolingian Empire,” The Transformation of Frontiers from Late Antiquity to the Carolingians, ed. Walter Pohl, Ian Wood, and Helmut Reimitz. Leiden: Brill, 2001, 219‒32, and the literature cited in these two studies. Also see the important new synthesis by Willner Heinz, Limes Saxoniae: Die Wiederentdeckung einer lange vergessenen Grenze. Marburg: Tectum Verlag, 2011. 44 ARF, anno 809 (see note 22), p. 129. 45 See, for example, the discussion by Volker Hermann, “Der ‘Limes Sorabicus’ und Halle im frühen Mittelalter,” Siedlung, Kommunikation und Wirtschaft im westslawischen Raum: Beiträge der Sektion zur slawischen Frühgeschichte des 5. deutschen Archäologenkon- gresses in Frankfurt an der Oder. Halle a. d. Saale: Beier and Beran, 2007, 133‒43. Mediaevistik 33 . 2020 109

46 With respect to the Germar Mark, see Bachrach, Charlemagne’s Early Campaigns 768‒777 (see note 4), 584‒89, 601‒02, and the literature cited there. 47 The Sorbian march and Henry’s conquest of the Sorbs are treated in detail by David S. Bachrach, “Restructuring the Eastern Frontier: Henry I of Germany, 924‒936,” Journal of Military History 78 (2014): 523‒56. 48 Regarding the Danevirke, and its size in relation to other early medieval defensive moats, see Paolo Squatriti, “Digging Ditches in Early Medieval Europe,” Past and Present 176.1 (2002): 11‒65, who although thoroughly underestimating the amount of work involved in the project, nevertheless recognizes the great scale of the Danish undertaking. For a more specifically military investigation of the Danevirke, see Andres Siegfried Dobat, “Dane- virke Revisited: An Investigation into Military and Social-Political Organisation in South Scandinavia (c. AD 700‒1100),” Medieval Archaeology 52 (2008): 27‒68 49 Goldberg, Struggle for Empire (see note 5), 244; and Bowlus, Franks, Moravians, and Magyars (see note 6), 62‒63. 50 See, for example, Cenek Stana, “Prerov- eine Burg des Boleslav Chrobry in Mähren,” Frühmittelalterliche Burgenbau in Mittel und Osteuropa, ed. Joachim Henning and Al- exander T. Ruttkay. Bonn: Habelt, 1998: 49‒69; Ludek Galuska, “Die großmärischen Sied- lungsagglomeration Staré Mesto-Uherské Hradisté und ihre Befestigungen,” Frühmittel- alterliche Burgenbau, 341‒48; and Pavel Kouril, “Frühmittelalterliche Befestigungen in Schlesien und Nordmähren,” Frühmittelalterliche Burgenbau, 349‒58. 51 See, for example, the discussion by Werner Budesheim, “Der ‘limes saxoniae’ nach der Quelle Adams von Bremen, insbesondere in seinem südlichen Abschnitt,” Zur slawischen Besiedlung zwischen Elbe und Oder, ed. Werner Budesheim. Wentorf bei Hamburg: Freie lauenburgische Akademie für Wissenschenschaft und Kultur, 1994, 28‒43; and Hardt, “The Limes Saxoniae” (see note 43), 39. 52 ARF (see note 22), anno 809, p. 129, “postquam locus civitati constituendae fuerat explo- ratus, Egbertum comitem huic negotio exsequendo, praeficiens Albim traicere et locum iussit occupare.” 53 See the discussion by Bernard S. Bachrach and David S. Bachrach, “Landscapes of De- fense: At the Nexus of Archaeology and History in the Early Middle Ages,” Francia 42 (2015): 231‒52. 54 See, for example, the useful collection of essays in The Defence of Wessex. The Burghal Hidage and Anglo-Saxon Fortifications, ed. David Hill and Alexander R. Rumble. Man- chester: Manchester University Press, 1996; and also the studies by Stuart Brookes, “Map- ping Anglo-Saxon Civil Defense,” Landscapes of Defence in Early Medieval Europe, ed. J. Baker, S. Brookes, and A. Reynolds. Turnhout: Brepols, 2013, 39‒63; Neil Christie, Oliver Creighton, and Matt Edgeworth, “Wallingford: Place, Space, and Defence,” Landscapes of Defence, 111‒27; and Richard Abels, “The Costs and Consequences of Anglo-Saxon Civil Defence, 878‒1066,” Landscapes of Defence, 195‒222. 55 Walter Schlesinger, Die Entstehung der Landesherrschaft, Part I. Dresden: Baensch, 1941, 79. 56 Paul Grimm, Handbuch vor- und frühgeschichtlicher Wall- und Wehranlagen. Teil I: Die vor- und frühgeschichtlichen Burgwälle der Bezirke Halle und Magdeburg. Berlin: Aka- demie Verlag, 1958. 57 Grim, Handbuch (see note 56), 44‒46. 58 The Carolingian preparations along the Spanish March are discussed in the ARF (see note 22), anno 778, pp. 50, 52; and Annales qui dicitur Einhardi, ed. F. Kurze, Monumenta Germaniae Historica, Scriptores in Usum Scholarum. Hanover: Monumenta Germaniae Historica 1895, anno 778, pp. 51, 53 For the military institutions of the Spanish March, see Bernard S. Bachrach, “Military Organization in Aquitaine under the Early Carolingians, 110 Mediaevistik 33 . 2020

Speculum 49 (1974): 1‒33, here 24‒31; Cullen J. Chandler, “Between Court and Counts: Carolingian Catalonia and the Aprisio Grant, 778‒897,” Early Medieval Europe 11 (2002): 19‒44; and Philippe Sénac, Les Carolingiens et al-Andalus (VIIIe‒IXe siècles. Paris: Mai- sonneuve et Larose, 2002, 51‒110, with the literature cited there. 59 The system of fortifications planned by Charles the Bald is set out in the famous edict of Pîtres in 864. See Capitularia II (see note 18), no. 273. This text is discussed in some detail by Nelson, Charles the Bald (see note), 207. Also see the treatment of Charles the Bald’s fortified bridges by Carroll M. Gillmor, “The Logistics of Fortified Bridge Building on the Seine Under Charles the Bald,” Anglo Norman Studies 11 (1989): 87‒106. However, also see the argument by Simon Coupland, “The Fortified Bridges of Charles the Bald,” Journal of Medieval History 17.1 (1991): 1‒12, that Charles constructed only two long-term fortified bridges, and otherwise relied upon temporary barriers across rivers to interdict Viking raids. 60 Regarding the costs that were involved in constructing fortifications, see the discussion by David S. Bachrach and Bernard S. Bachrach, “The Costs of Fortress Construction in Tenth-Century Germany: The Case of Hildagsburg,” Viator 45.3 (2014): 25‒58. 61 For an overview of this campaign, see the discussion by Bachrach, “Military Organization in Aquitaine under the Early Carolingians” (see note 58), 1‒33. 62 ARF (see note 22), anno 808, p. 126. 63 Astronomer, Vita Hludowici imperatoris, ed. and trans. Ernst Tremp, MGH SRG, 64. Hanover: Monumenta Germaniae Historica, 1995, ch. 42. According to the author of the ARF (see note 22), anno 829, p. 127, in July 829, while Louis the Pious was still at Aachen, he received word that the Vikings were planning an attack on the Saxon region, and mo- bilized a large army to oppose them. Ultimately, however, this information proved to be false. 64 Astronomer, Vita Hludowici imperatoris (see note 65), ch. 42. 65 Nithard, Historiarum libri quattuor, ed. G. H. Pertz 3rd edition. MGH SRG, 44. Hanover: Monumenta Germaniae Historica, 1965), 2.1, p. 404, “ipse autem, pedetemptim, quo se res verteret, antequam Alpes excederet, scire volens.” There are no significant differences between this edition and Nithard: Histoire des fils de Louis le Pieux, ed. and trans. Philipe Lauer and revised by Sophie Glansdorff. Paris: Les Belles Lettres, 2012. 66 Annales Bertiniani, ed. Georg Waitz MGH SRG, 5. Hanover: Monumenta Germaniae His- torica, 1883, anno 866, p. 82. 67 Annales Fuldenses, ed. F. Kurze, MGH SRG, 7. Hanover: Monumenta Germaniae Histori- ca, 1891, anno 858, p. 48‒49. 68 Annales Fuldenses (see note 67), anno 858, p. 48‒49 69 Annales Fuldenses (see note 67), anno 858 p. 48‒49 70 Annales Fuldenses (see note 67), anno 858, p. 48‒49. The report of the dispatch of Tha- culf’s army is placed out of order in the entry for 858 alongside the discussion of the dispatch of armies under Louis’s sons Carloman and Louis the Younger against the Mora- vians, and the Abodrites, respectively. 71 Annales Fuldenses (see note 67), anno 871, p. 74‒75. 72 Annales Fuldenses (see note 67), anno 880, p. 94‒95. 73 Annales Fuldenses (see note 67), anno 880, p. 94‒95. 74 ARF (see note 22), anno 827, p. 172‒73. 75 ARF (see note 22), anno 827, p. 172‒73 76 ARF (see note 22), anno 828, p. 174‒75. 77 ARF (see note 22), anno 828, p. 174‒75. The two counts who were removed from office were Hugh of Tours and Matfrid of Orléans. This same account is provided by the Astro- Mediaevistik 33 . 2020 111

nomer, Vita Hludowici imperatoris (see note 65), ch. 41‒42, who provides the names of the commanders of the Frankish columns. 78 ARF (see note 22), anno 828, p. 174. 79 Astronomer, Vita Hludowici (see note 65), ch. 15. 80 Astronomer, Vita Hludowici (see note 65), ch. 15. 81 Astronomer, Vita Hludowici (see note 65), ch. 15. 82 See, in this context, the important work by Justin C. Lake, “Truth, Plausibility and the Vir- tues of Narrative at the Millennium,” Journal of Medieval History 35 (2009): 221‒38, who emphasizes the Ciceronian tradition, current in much of early medieval historiography, that emphasized the necessity of presenting an account that was plausible to the audience. 83 Notker the Stammer, Gesta Karoli Magni Imperatoris, ed. Hans F. Haefele. MGH Scrip- tores Rerum Germanicarum Nova Series, 12. Berlin: Monumenta Germaniae Historica, 1959, 2.14. 84 Notker, Gesta Karoli (see note 83), 2.14. 85 Regino of Prüm, Chronicon, ed. Friedrich Kurze MGH SRG, 50. Hanover: Monumenta Germaniae Historica, 1890, anno 891, p. 137‒38. 86 Regino of Prüm, Chronicon (see note 85), anno 891, p. 137‒38. 87 Annales Vedastini, ed. B. von Simson, MGH Scriptores Rerum Germanicarum, 12. Hano- ver: Monumenta Germaniae Historica, 1909, anno 881. 88 Annales Vedastini (see note 87), anno 881, p. 50. 89 Annales Vedastini (see note 87), anno 886, p. 61. 90 Annales Vedastini (see note 87), anno 886, p. 61: “volens invisere qualiter exercitus castra eorum possent adtingere, vel quo ipsi castra figere deberent.” 91 Annales Vedastini (see note 87), anno 886, p. 61. 92 Annales Fuldenses (see note 76), anno 891, p. 120. 93 Nithard, Historiarum (see note 65), 2.6, p. 404. 94 Nithard, Historiarum (see note 65), 2.6, p. 404. 95 Nithard, Historiarum (see note 65), 2.6, p. 404. 96 De Ordine palatii (see note 10), lines 494‒500. 97 Annales Fuldenses (see note 67), anno 876, pp. 88‒89. 98 Annales Bertiniani (see note 66) anno 876, p. 132‒33. 99 Annales Fuldenses (see note 67), anno 876, pp. 88‒89. 100 Annales Fuldenses (see note 67), anno 876, pp. 88‒89. Also see the discussion of this battle by Bernard S. Bachrach and David S. Bachrach, “Saxon Military Revolution, 912‒973?: Myth and Reality,” Early Medieval Europe 15 (2007): 186‒222, particularly 210‒11.