To understand the Arab conquests we need to go back all the way to the second and third centuries ad, when the Roman Empire made a great push to the east. This began with Emperor Trajan's war of ad 106 against Persia and was followed up by numerous expeditions eastward by high-ranking military men and emperors. One by one they annexed the lands of the once-independent dynasties of Petra, Palmyra, and Edessa, which brought Rome into direct contact with the pastoralist tribes that these dynasts had formerly managed on her behalf. Under Emperor Septimius Severus (193—211) two extra legions were created for service in the east, meaning that eight legions were now stationed in the zone that stretched from the new province of Mesopotamia (in modern southeast Turkey and northwest Iraq) southward to Arabia. It looked as though Rome would gradually come to dominate the whole of the Middle East. However, the game changed in 224 when the energetic Sasanian dynasty took over the Persian Empire (which comprised Iraq and Greater Iran), for it pursued a more centralizing and expansionist policy than its predecessors.3 The Sasanians launched a series of devastating attacks upon Rome's eastern flank in the mid-third century, achieving numerous victories and even managing to capture the Roman emperor himself. Only the intervention of the prefect of Palmyra, who rallied an army of townsmen and tribesmen, saved Rome from Persia's seemingly unstoppable onslaught. Thereafter the two empires came to a grudging acceptance of one another, eyeing each other warily across the Syrian desert, mostly respecting each other's sovereignty except for occasional skirmishes and forays to extract tribute and captives and to make a show of strength for audiences back home (Figure I. I).
Though the western portion of the Roman Empire suffered instability and loss of territory during the fourth and fifth centuries, the eastern part continued to flourish, now based at a new capital, Constantinople, on the site of the ancient Greek city of Byzantium, which is the name that modern scholars use when referring explicitly to the Christian East Roman Empire (though its own citizens kept thinking of themselves as Romans). The geopolitical situation described earlier—the empires of Byzantium and Persia in a sort of cold
FIGURE I. I Emperor Justinian I at court: mosaic, San Vitale, Ravenna; Yazdgird III at hunt: silver plate, Bibliotheque Nationale, Paris. Note the very different styles of legitimation and projection of power practiced by these two empires.
War standoff—remained relatively stable through the fourth and fifth centuries, but the sixth century witnessed a sharp escalation in hostilities. Major clashes occurred in 530—32, 540—45, and 572—90. The last of these confrontations ended on a hopeful note. The youthful Persian emperor Khusrau II fled to Constantinople, seeking the Byzantines’ help against rival challengers at home. Khusrau was granted troops and he went on to successfully recapture his throne; all looked set for a new era of peace and cooperation between these two superpowers. However, when Byzantium was rocked by a military coup in 602, Khusrau decided that the time was ripe to renew hostilities and he launched an all-out attack on his erstwhile ally. The onward march of his forces seemed impossible to check: Syria was captured by 6I0, Palestine by 6I4, Egypt by 619, and Anatolia as far as the walls of Constantinople itself by 626. Yet the Byzantine emperor Heraclius, who had wrested the imperial throne from its usurper in 6I0, made a dramatic comeback by marching through the Caucasus and attacking Persia from the north, supported by a large contingent of Turks.
This enabled him to strike at the heart of his enemy's empire, advancing on the capital, Seleucia-Ctesiphon, sacking royal residences as he went and putting the defeated and disgraced Khusrau to flight.
At one point it had looked as though the Persians were going to steal the whole show; thus in the very early seventh century the head of the Georgian church told his Armenian counterpart: “The king of kings (Khusrau II) is the lord of the Romans as much as of the land of the Aryans.”4 But now the tables were turned and Heraclius was able to dictate terms to a humbled Persia. Khusrau's son made peace with Heraclius in 628 and agreed to restore to the Byzantines all of the lands seized by the Persian troops. In 630 Heraclius celebrated the triumph of the Christian world by restoring the relics of the cross of Jesus to Jerusalem, entering the city in great pomp and ceremony, only sixteen years after its sack at the hands of the Persians. Again, all looked set for an irenic future, and the picture looked even rosier for the Byzantines, when the general Shahrbaraz, who “had presented himself to Heraclius as a slave” and whose son had become a Christian, acceded to the Persian throne in April 630 with the aid of “Persian and Byzantine troops.”5 It looked as though Persia would become a vassal of Byzantium and possibly even a Christian one at that. But yet again these hopes of a lasting peace between the two superpowers were shattered. Shahrbaraz was not of the royal house of Sasan and, despite the endorsement of Heraclius, was murdered by disgruntled Persian nobles. The Persian Empire descended into civil war, leaving its borders, already neglected during its quarter-century long conflict with Byzantium, woefully exposed.
World History
