View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Humanities Commons Buried Under? Re-examining the Topography and Geology of the Allia Battlefield Introduction The territory of the Roman Empire abounds with battlefields – about twenty of them are documented in literary sources from the fifth and fourth centuries BC alone. However, they have not received much attention from archaeologists, partly because of problems pertaining to their exact identification and the lack of actual material evidence1. The two notable exceptions to this rule are the archaeological studies of the battle site of Lake Trasimene and the extensive battle site of Teutoburg2. The battlefield of Allia near Rome (Figure 1), on the other hand, falls into line with the majority of Roman battlefields, as it has not attracted much attention from archaeologists. A clash between Romans and Gauls (or Celts) at this site ended in victory for the latter, resulting in the capture and sack of Rome around 390 BC or later in the 380s, depending on how the literary sources are interpreted. Although the battle is frequently mentioned in studies regarding Republican Rome,3 it is often discussed only by referring to the accounts of the three main authors describing the incident, namely Livy4, Diodorus Siculus5, and Plutarch6. While these accounts are detailed, they were written several centuries after the battle and are therefore likely to incorporate legends and myths in addition to genuine tradition. Notable historical research concerning the battle was conducted in the late 19th and early 20th centuries,7 but recently the battle has received little attention from scholars. One 1 J. Coulston, “The archaeology of Roman conflict”. In P. Freeman and A. Pollard, eds. Fields of Conflict: Progress and Prospect in Battlefield Archaeology, Oxford 2001, 26. 2 G. Susini, Ricerche sulla Battaglia del Trasimeno, Cortona 1960. Concerning the battle of Teutoburg, see Strabo 7,1,3 and concerning studies conducted at the site, see A. Rost, “Characteristics of ancient battlefields: Battle of Varus (9 AD)”. In: D. Scott, L. Babits and C. Haecker, eds. Fields of Conflict. Battlefield Archaeology from the Roman Empire to the Korean War, Washington (D.C.) 2009, 50–57; S. Wilbers-Rost, “Total Roman defeat at the Battle of Varus ( 9 AD)”. In: D. Scott, L. Babits and C. Haecker, eds. Fields of Conflict. Battlefield Archaeology from the Roman Empire to the Korean War, Washington (D.C.) 2009, 121–132. 3 E.g. E. Meyer, Geschichte des Altertums, Stuttgart/Berlin 1902; L. Hartmann, “Die äufsere Geschichte Roms bis zur Einigung Italiens“ In L. Hartmann and J. Kromayer, eds. Römische Geschichte, Gotha 1921, 41–55; L. Pareti, Storia di Roma, Torino 1952; H. Scullard, A History of the Roman World 753 to 146 BC, London 1969. 4 Livy Ab. urb. cond. 5,37,1–5,38,10. 5 Diod. Sic. 14,114,1–14,115,2. 6 Plut. Cam. 18,4–7. 7 T. Mommsen, Hermes 13 (1878) 515–555; C. Hülsen and P. Lindner, Die Alliaschlacht. Eine Topographische Studie, Rome 1890; O. Richter, Beiträge zur Römische topographie, Berlin 1903; G. De Sanctis, Storia dei Romani 2, Milano 1 exception is the monograph by Lorenzo Quilici and Stefania Quilici Gigli, which focuses on the survey results of the ancient settlement of Crustumerium.8 A significant section of this monograph is devoted to the identification of the Allia battlefield via topographical means. Beyond this, the discussion of the battle itself largely follows the accounts of the ancient authors. However, as Quilici and Quilici Gigli ponder the exact location of the Allia battlefield, they make interesting passing references to the possibility that the course of the Tiber River could have changed with the centuries.9 Unfortunately, they do not develop this argument much further. For this reason, the main aim of this paper is to provide an answer to this very question: might the course of the Tiber have changed during the past 2400 years, and if so, how much? Depending on the answer, the accountability of the ancient authors writing about the Battle of Allia might also be re- evaluated. To reach this point, various sources of information regarding the topography, geology, and hydrogeology of the presumed location of the Allia battlefield must be scrutinized. This material includes historical and geological maps and aerial photographs, as well as the extensive literature pertaining to the geology and geography of the region. It will be shown that the course of the Tiber has always been and continues to be in constant change and that these changes very likely explain the mutually contradictory statements made by the ancient authors. In addition, it will be claimed that especially the horizontal topography in the area has been transformed to such an extent that the exact location of the battlefield cannot be reliably pinpointed without new archaeological data. To reach such a conclusion, it is essential to first provide a short outline of this clash between the Romans and the Gauls and its location as reported in literary sources. In addition, it is also essential to review how the question of the location of the battlefield has been dealt with in previous research. Only then can we focus on details regarding the topography and geology of the area. 1907; E. Kornemann, Klio 11 (1911) 335–342; J. Kromayer, Abhandlungen des Sachsichen Gesellschaft 34 (1916) 28– 59; J. Kromayer and O. Veith, Schlachten-Atlas zur antiken Kriegsgeschichte, Leipzig 1922; F. Schachermeyr, Klio 23 (1930) 277–305. 8 L. Quilici and S. Quilici Gigli, Crustumerium, Roma 1980, 39–44, 162–168, 291–294, 298, see also pl. 105. 9 L. Quilici and S. Quilici Gigli (above n. 9), 161, 168, 292. 2 The present paper can be said to represent battlefield archaeology, a recognized subfield and an integral part of conflict archaeology, which has gained prominence only in the last two decades or so10. As the name itself suggests, this subfield focuses on the identification and study of battlefields and battles via archaeological means. The correct identification of a battlefield is an integral part of this process, which relies heavily on historical documentation, thus placing the subfield within the scope of historical archaeology. As battlefield archaeology is concerned with the actual site of the battle, its reliance on historical evidence is understandable. While the existence of prehistoric battles and warfare is hardly doubted and direct evidence of such events is available in the form of skeletal and other material evidence, it would be very hard to identify a battlefield without historical evidence pointing in the right direction. When a prospective site for a battlefield has been identified, archaeological fieldwork methods may be applied to determine whether the identification is correct. For example, electromagnetic conductivity surveys can be used to detect subsurface anomalies, metal detection surveys to detect metal artefacts pertaining to the battle, and GIS methods to study topography and/or visualize and study the results of fieldwork surveys11. In some cases, often when the site has been identified reliably, it may also be prudent to conduct archaeological excavations.12 However, archaeological fieldwork is relevant only when the rough identification based on historical sources has already produced a viable candidate, or at most a few candidates, for the site of the battle. As this paper in part demonstrates, this is often not an easy task. Arguably, the task of identifying a battle site correctly becomes more and more challenging as time passes since the event itself. Furthermore, during the centuries – perhaps even millennia, like in the present case – several post-depositional factors may have destroyed, removed, and/or altered the 10 See e.g. T. Pollard and I. Banks, eds. Past Tense. Studies in the Archaeology of Conflict, Leiden 2006; D. Scott, L. Babits and C. Haecker eds. Fields of Conflict. Battlefield Archaeology from the Roman Empire to the Korean War, Washington (D.C.) 2009. 11 G.M. Pratt, “How do you know it’s a battlefield?” In: D. Scott, L. Babits and C. Haecker, eds. Fields of Conflict. Battlefield Archaeology from the Roman Empire to the Korean War, Washington (D.C.) 2009, 6–9. 12 A. Rost (above n. 3); S. Wilbers-Rost (above n. 3). 3 evidence on site, making the archaeological verification of a battlefield difficult, if not impossible.13 These problems are compounded if the battle was fought in an environment that is topographically unstable in some way, as landmarks that may once have marked the site of the battle might not exist today or their positions might have shifted. As demonstrated below, the Battle of Allia is an exemplary case of such an event. The Battle and Battlefield of Allia At the time of the Battle of Allia, the Romans fought in a Greek-style hoplite phalanx consisting of heavily armed infantrymen.14 The phalanx required level ground for the battle, as it was impossible to maintain the tight formation on uneven ground.15 The topography of the presumed Allia battlefield therefore seems to match the features common to sites of hoplite engagements rather well16. The battlefield is a level plain naturally enclosed by topographical features and observable from a nearby settlement (Crustumerium), and a road (Via Salaria17) – a common feature for a site of hoplite engagement18– led directly to the site. It is also worth noting that this is the area where the Tiber river valley narrows down from 3 km to 1.5 km within a stretch of only five kilometres downstream. This feature probably influenced the selection of the battle site, as the Roman army – composed of 24,000–40,000 men, according to the ancient authors19 – had to fit into the local topography in an optimal manner to act efficiently as a 13 See J.