Iranica Antiqua, vol. XLVI, 2011 doi: 10.2143/IA.46.0.2084424 DISINTEGRATION OF SASANIAN HEGEMONY OVER NORTHERN IRAN (AD 623-643)1 BY Mehrdad GHODRAT-DIZAJI (Urmia University, Iran) Abstract: From the 6th century AD onward, the Sasanian Empire tried to build up its military strength and defense system by dividing the country into four Kusts or quarters and erected fortifications and fortified walls in each Kust. One of these defensive walls was erected in the northern Kust in order to defend the borders of the empire against northern nomads. Perhaps the most important defensive walls of the empire in the northern quarter were in the passes of the northern Caucasus, especially at Darband. These fortifications were heavily damaged in the course of Sasanian-Byzantine wars (AD 603-628), which lead to the defeat of the Sasanian Empire. This was the advent of the disintegration of the Sasanian dynasty, which was later completed by Arab Muslim raids. The study of the archaeological, numismatic and literary evidence reveals that from this time (AD 623) onward, the Sasanians lost their control over the northern quarter and only practiced their weak domination over western and southern parts of the empire. The situation was like this until the downfall of the Sasanian dynasty through Arab Muslims and their penetration into Adurbadagan (AD 643). Keywords: Adurbadagan; defensive system; northern quarter; Sasanians. Introduction One of the most interesting topics in Sasanian studies, which has attracted the attention of scholars in the last two decades, is the historical and admin- istrative circumstances of Iranian provinces during the late Sasanian and early Islamic periods. This issue has been under investigation about Fars, Iraq, Khuzistan and Sistan provinces and even now the investigations are still underway (cf. e.g. Bosworth 1968; Morony 1982; Gyselen 2000; 1 The author wishes to thank Dr. Rika Gyselen and Dr. Vesta Sarkhosh Curtis for their helpful comments and suggestions on earlier drafts of this article. Any shortcomings, of course, are my own. 994066_Iran_Antiqua_46_13.indd4066_Iran_Antiqua_46_13.indd 331515 221/06/111/06/11 112:392:39 316 M. GHODRAT-DIZAJI Daryaee 2002; Robinson 2004). Despite the importance of Azerbaijan for the Sasanians, and especially the end of that period, the disintegration of Sasanian hegemony over that area has not been thoroughly studied and many issues have still remained unsolved2. V. Minorsky’s well-known study on the Roman and Byzantine campaigns in Atropatene during the reign of Emperor Khusrow II (AD 590-628) is still of great importance (Minorsky 1944). However, with regard to Azerbaijan after the death of Khusrow, which is known as a period of chaos, not much study has been carried out. In our study of the area, we do not expect the same number of sources available as, for example, a study of Fars and Iraq. However, an analysis of present sources and the process of events demonstrate that the disintegration of Sasanian rule in this province had already begun with the defeat of Sasanian forces by the Byzantine army of Emperor Heraclius (AD 610-641) in AD 627 and the death of Khusrow II in AD 628. After that, the province was no longer within the power of the Sasanians. In other words, the fall of the Sasanian army in Azerbaijan happened before the fall of Iraq and Fars. It seems that the collapse of Sasanian rule in Azerbaijan contributed considerably to their defeat in Iraq and other provinces. With the loss of the province of Azerbaijan, which was considered as the centre of warriors by the Sasanians from the beginning of their history (cf. Ghodrat-Dizaji 2007: 88), and the site of the most important fire temple, the Sasanians were deprived of one of their military and spiritual capabilities. The Sasanian System of Defense in Northern Iran Modern authors have shown that Sasanians erected walls and moats along their borders, especially in Mesopotamia, the Caucasus and in the north-east, and they settled colonies in those regions to defend Eransahr (Land of the Iranians) (cf. Kramers 1933-37: 613-618; Frye 1977: 7-8; Harmatta 1996: 80; Mahamedi 2004: 146). It is stated that a quadriparti- tion of the Sasanian Empire was part of Khusrow I’s (AD 531-579) reforms to defend Iranian borders. As we know, Sasanians at that time transformed old divisions of the Empire into provinces and divided the Empire into four 2 The administrative conditions of the province have been studied recently by the author; cf. Ghodrat-Dizaji 2007, 2010. 994066_Iran_Antiqua_46_13.indd4066_Iran_Antiqua_46_13.indd 331616 221/06/111/06/11 112:392:39 DISINTEGRATION OF SASANIAN HEGEMONY OVER NORTHERN IRAN 317 quarters or sides (kust in Pahlavi). They then appointed a general (spahbed in Pahlavi) at the head of each kust. These four quarters were called: xwarasan (East), xwararan (West), nemroz (South), and abaxtar (North). Each of the kusts included provinces which were governed by a marzban (border guard) whose headquarter was at the centre of the province (Gyselen 2001: 14, 35-45; Baladhuri 1968: 325-326). According to Islamic literary sources, the northern quarter or kust came into existence by the integration of several provinces in Iran and the Caucasus (Azerbaijan, Gilan, Albania …) in the sixth century AD, and was named after Adurbadagan/Azerbaijan, its most important province3. However, there are some disparities between literary and epigraphical sources about the provinces of this kust. While literary sources locate provinces such as Armenia, Georgia, Gilan and ™abaristan in the northern quarter, most recent studies in Sasanian seals have shown that Armenia, Sahr-i Mugan (on the western shore of the Caspian Sea), and Baza (Balasakan?) were not part of this northern quarter (cf. Gyselen 2009: 291-292). The Sasanians penetrated into the Caucasus from earlier times and erected fortifications there in order to defend the borders of the empire against northern nomads. They also settled there tribes and their subjects, mainly from the southern Caspian region (Nöldeke 1879: 157; Kramers 1935-37: 613-614; Christensen 1944: 369; Alltheim & Stiehl: 1954: 138- 139)4. Perhaps the most important defensive walls of the empire in the northern quarter were in the passes of the northern Caucasus, especially in Darband. The city and the fortifications of Darband which were built by the Sasanians in the 5th and 6th centuries AD, were part of the northern limes of the Sasanian Empire, which were extended along the western coast of the Caspian Sea (Baladhuri 1968: 194-195; Huff 1981: 132-133). The fortifications consisted of two parallel walls that formed a barrier from the seashore up to the mountain, and the town was built between these two walls (cf. Kettenhofen 1996: 13-19; Powell 2008: 36-41). The ancient city of Darband and its defense structures have been crucial for the control of 3 The title of Adurbadagan amargar is attested on the inscriptions of Darband; cf. Christensen 1944: 123; for details cf. Ghodrat-Dizaji 2010. 4 According to Kramers (1935-37: 618), the term for the Sasanian military colonists, corrupted in Arabic texts, derives from Pahlavi origin, nisastak. It may be added that the term nisastangah was used in new Persian (e.g. in Firdowsi 1970: 96) when referring to the residence of kings and nobles of the Sasanian period. 994066_Iran_Antiqua_46_13.indd4066_Iran_Antiqua_46_13.indd 331717 221/06/111/06/11 112:392:39 318 M. GHODRAT-DIZAJI the north-south passage on the west side of the Caspian Sea for the Sasan- ians against the invasion by the nomadic peoples, especially Khazars (cf. Frye 1977: 11-12)5. One of the most important duties of the spahbed of the North and his forces was to guard these fortifications against the raids of the Khazars into Sasanian domain (Nöldeke 1879: 155 n. 2; Christensen 1944: 369-370; Altheim & Stiehl 1954: 138). We can imagine that resistance against invasions of Barbarians would have been of utmost importance for the Sasanians. Hence, they took this into consideration and invested heavily in protecting the Caucasus and Darband fortifications. In addition, the maintenance and repair of the Darband fortifications were of great impor- tance to both the Sasanian and Byzantine Empires. Payment for high main- tenance costs of these fortifications was often included as a term in different peace treaties between Khusrow I and the Byzantines (Marquart 1901: 94-118; Christensen 1944: 238-239, 281, 373; Mahamedi 2004: 15). Kavad I (AD 488-496, 499-531) and Khusrow I had especially taken vast measures against such raids in the Caucasus. It was only when Khusrow II’s army was defeated by the Byzantine Emperor Heraclius that the Khazars were able to move southwards to Darband and raid provinces of northern Iran. Byzantine Wars and the Destruction of Sasanian Domination in the North After a cordial relationship between the Sasanians and the Byzantines (AD 590-603), twenty five years of war between two empires began and “the last Great War of antiquity” (Howard-Johnston 1999: xxii) (AD 603- 628) started. This marks the greatest turning point in the history of the two empires. It was during this war that Khusrow II engulfed Iran into one of the most devastating warfare in her history (on the course of events cf. Rawlinson 1876: 510-520; Minorsky 1944: 248-251; Greatrex & Lieu 2002: 198-228; Dignas & Winter 2007: 44-49). In AD 622, during the last phases of war, Heraclius initiated a series of annual campaigns against the Sasanians, which very soon resulted in a reversal of fortune in favour of 5 A joint team of British and Iranian archaeologists have excavated at the Great Walls on the Eastern side of the Caspian Sea. Extending from the Caspian Sea eastward, the mud-brick wall was erected perhaps to secure the empire against the threat posed by the Hephtalites.