Confrontation

The Greco-Roman world has always had close contacts of a multifarious nature with the Near Eastern cultures. The Greeks and Macedonians had their interactions and confrontations with the Achaemenid Persians in the fifth and fourth centuries BC, and the Romans with the Parthians from the first century BC onward. A superpower on its eastern frontier was therefore not a new phenomenon for the Roman Empire. New was the fresh vigor of that superpower after the gradual weakening of the Parthian Empire in the second century ad (although the Parthians were still strong enough to defeat a Roman army at Nisibis in ad 217). The struggle for the Arsacid throne between the brothers Vologeses VI and Artabanus IV offered the Sasanians - local leaders in the region of Fars in southeastern Persia - the possibility to revolt, to replace the Arsacids, and to establish their power. Although much is unclear about the course of this revolt, it is generally accepted that it started in ad 205-6 and ended in AD 226 with the coronation of Ardashir as king of kings in the capital Ctesiphon (Christensen 1944: 84-96; Schippmann 1990: 10-17). From the beginning, the Sasanian policy toward Rome was aggressive. To sustain and legitimate their position as rulers over the empire, the Sasanian kings had to show their superiority toward internal rivals by successes and victories on the battlefield. Moreover, it is possible that the Sasanians presented themselves as heirs of the Achaemenids, with the intention of restoring the old Iranian kingdom, of which some of the eastern provinces of the Roman Empire had been a part (Whitby 1994: 234-5; Rubin 2000: 646-7; but see Yarshater 1971). Although Sasanian armies sometimes penetrated deep into Roman territory, and Roman armies reached the Persian heartland, warfare was chiefly focused on the rich and important cities in northern Mesopotamia that lay in the border region between the two empires (Isaac 1998a: 459). The desire to control Armenia, the buffer state between the two nations, made the area a constant scene of conflict.

The relations between the Sasanian and Roman Empires went through three main phases (Whitby 1988: 202-11). The first (ad 226-363) is characterized by an aggressive attitude toward Rome on the part of the Sasanians, by Rome’s slow adaptation to its new aggressive neighbor, and by serious hostilities initiated from both sides. The second phase (ad 363-C.500) saw only a few conflicts, and is characterized by coexistence and cooperation. The third phase (c. ad 500-C.630) is marked by increasing mutual suspicion and warfare, but also by short periods of cooperation and understanding.

Shortly after he had come to power, Ardashir undertook several campaigns into Roman territory and captured the important cities of Nisibis, Carrhae, and Hatra; but the greatest successes were won by his son and successor Shapur I (Frye 1984: 296303; Millar 1993: 159-67; Winter and Dignas 2001: 40-3). In ad 244, he defeated the Roman emperor Gordian, who possibly fell in that battle. In a devastating campaign in ad 253, Shapur ravaged northern Syria, took Hierapolis, managed to penetrate Roman territory as far as Antioch, and captured this third largest city of the Roman Empire (Downey 1961: 252-9). His third victory was even more humiliating for the Romans, since he not only defeated the emperor Valerian (ad 253-60) in a battle near Edessa (ad 260), but also took the emperor captive (Schippmann 1990: 23; Dodgeon and Lieu 1991: 57-65). Valerian was never to return and died in Sasanian captivity, possibly in the city of Gundeshapur (‘‘the weapons of Shapur’’), which was built with the manpower of the thousands of Romans Shapur had taken prisoner. After Shapur’s death the Sasanid Empire suffered from a temporary weakness, of which the Romans were able to make use. Under the emperor Diocletian (ad 284-305), the defenses in the eastern frontier zone were reorganized and strengthened (Isaac 1992: 163 ff.). In ad 283, the Romans sacked the Sasanian capital Ctesiphon, and Diocletian’s co-emperor Galerius (ad 293-311) won another great Roman victory. The subsequent peace treaty of ad 298/9 was very disadvantageous for the Sasanians: they lost considerable territory - the river Tigris would constitute the new border - and the Romans gained far-reaching influence in Mesopotamia, Armenia, and Iberia; important cities in northern Mesopotamia such as Nisibis were now within the boundaries of the Roman Empire (Blockley 1992: 5-7; Dodgeon and Lieu 1991: 125-35). From now on, Rome’s posture toward the eastern neighbor was only defensive; but, out of dissatisfaction with the treaty of ad 298/9, the Persians revived their offensive policy again under Shapur II. In the later years of the reign of Constantine the Great (ad 306-37), whose universal christianizing policy undoubtedly fueled the aggressive Sasanian policy even more (Blockley 1992: 11), military intrusions into Roman territory were resumed, and continued under Constantius II (ad 337-61). In general, these military campaigns were of a small scale, and Shapur focused on regaining control of the cities in north Mesopotamia, which in these years were repeatedly besieged.

The character of warfare changed with the massive Roman expedition by the emperor Julian (ad 361-3) in ad 363. This expedition is very well documented, thanks to the historian Ammianus Marcellinus, who participated in it (Amm. Marc. 23-25. 3; Dodgeon and Lieu 1991: 230 ff.). The goals of the campaign are not entirely clear, but revenge for Shapur’s aggression toward the Roman Empire was certainly one of them (Boeft 2002: 208). The Roman forces reached Ctesiphon, but then returned and were utterly defeated by the Persians in trying to reach Roman territory. Julian himself was killed in one of the battles with the enemy (Amm. Marc. 25. 3), and his successor Jovian (ad 363-4) was to make peace with Shapur. Rome had to give up the lands east of the Tigris and northeastern Mesopotamia, as well as various important cities, Nisibis among them (Blockley 1992: 24-30). This shameful treaty, as Ammianus calls it (25. 7. 13), restored the balance of power between the two empires, which had been distorted by the treaty of ad 298/9, and introduced a long period of relative peace and stability.

In spite of the invasions of the Sasanian kings deep into Roman territory, and Roman military expeditions into the Persian heartland, it seems never to have been the intention of either power to occupy captured territory outside of north Mesopotamia permanently; many military encounters were basically wars of plunder. Although it was possibly the Sasanians’ intent to regain former Achaemenid holdings, and the Romans’ official policy was intrinsically imperialistic, both superpowers were also ruled by realism and knew that neither would be able to incorporate and hold conquered territory on a permanent basis (Blockley 1992: 106-7, 121 ff.). At least after ad 363, each power remained intent upon keeping control of the territory that it thought of as its own, and upon preserving a balance of power.

The second phase saw a division of influence in Iberia (ad 370) and Armenia (ad 387), two other contested regions between Rome and Persia (Blockley 1992: 42-5); this seems only to have strengthened the stability between the two powers. Two short wars were fought (ad 421-2; 440-1), both, it seems, provoked by the Persians - for religious and financial motives, but also in order to make more secure the precarious position of their king, who had to prove himself in strife with Rome (Blockley 1992: 56-7, 61; Greatrex 1998: 13). Until the beginning of the sixth century tranquility dominated the relations between Rome and Persia. Both powers were occupied with other foes: the Sasanians with the Hephthalite Huns on their northeastern border, and the Romans with Huns, Goths, Vandals, and Isaurians. In the Huns, coming from north of the Caucasus, Rome and Persia had a common enemy. It is not clear whether there was an agreement between Rome and Persia about Rome’s financial contribution to the maintenance of Persian defenses in the Caucasus against the Huns; but Rome’s failure to make regular payments to the Persians, together with increasing mutual suspicion, are both at times put forward as reasons for the renewal of hostilities between the two superpowers at the beginning of the sixth century (Greatrex 1998: 14-17).

The third phase started with the renewal of the Sasanian expansion policy. Between ad 502 and 532, the Sasanians invaded Roman territory regularly and successfully. In ad 532, the so-called ‘‘Eternal Peace’’ was concluded (Greatrex 1998: 213 ff.), which, however, only held out shortly. Worried by the successes of Justinian I (527-65) in the west, the Sasanians attacked the Roman Empire again in AD 540, under Khusro I. Antioch was captured and its population deported to the Sasanid Empire (Procop. Pers. 2. 8. 1-35; 9. 14-18; Downey 1961: 542-4). As before, warfare was confined to Mesopotamia and Armenia. Neither the Persians nor the Romans, now led by Justinian’s general Belisarius, were able to gain the upper hand. But in spite of several armistices, fighting regularly flared up again; formal peace was concluded only in ad 562 (Winter and Dignas 2001: 164-77). This peace was of short duration as well, and in ad 572, warfare was renewed (Whitby 1988: 219 ff.). This last long period of hostilities reached its climax during the reigns of Heraclius (ad 610-41) and Khusro II (ad 590-628). Initially, the Romans supported the latter against a usurper, but after regaining the Sasanian throne, he turned against them, proclaiming himself emperor over the Byzantine Empire. Due to internal weaknesses and strife over the imperial power in Constantinople, Khusro was able to conquer the eastern provinces of the Byzantine Empire (Schippmann 1990: 63 ff.; Winter and Dignas 2001: 136-40; Greatrex and Lieu 2002: 182-97). In particular, the fall of Jerusalem and the capture of the relics of the True Cross, the symbol par excellence of the Christian Byzantine Empire, may have been a tremendous shock to the Byzantines. Within a few years, however, Heraclius was able to reconquer the lost territory and, in ad 630, to return the Cross to Jerusalem (Drijvers 2002). At the beginning of the seventh century, the territory over which the Sasanians ruled came close to that of their Achaemenid predecessors; but their supremacy was short-lived. In the years ad 622-30, Heraclius brought about the downfall of the Sasanid Empire as a new Alexander (Howard-Johnston 1999). His reconquests led to anarchy in the Sasanid state, with some eight rulers in the years AD 628-32. When Yazdgerd III (ad 632-51) came to the throne, the empire was so weakened that it was unable to withstand the Muslim Arabs. In the years following the Sasanian defeat in the battle of Nihavand, in ad 642, the Muslims were able to conquer the Sasanid Empire and to occupy the territories over which Romans and Sasanians had fought for more than four centuries.