After the fall of Maurice a rumor spread that Theodosius had managed to escape, as his father had hoped, and reached Colchis, from where he made his way to Khusro's court (Theophylact 8.13.1–6). When, five months later, Lilius presented Phocas' credentials to Khusro as the new Roman emperor, he was repudiated. Khusro II dismissed Phocas as a usurping tyrant, and declared war with the aim of restoring Theodosius to his father's kingdom. Eastern sources helped to spread the word that the son had escaped (Theophylact 8.13.5; Armenian Chronicle Attributed to Sebeos 106, 110).
And so Chosroes exploited the tyranny as a pretext for war, and mobilized that world-destroying trumpet: for this became the undoing of the prosperity of Romans and Persians. For Chosroes feigned a pretence of upholding the pious memory of the emperor Maurice. And so in this way the Persian war was allotted its birth, and Lilius remained among the Persians in great hardship. In these days error came upon the inhabited world, and the Romans supposed that Theodosius was not dead. And this became an opportunity for great evils, and this false supposition contrived an abundance of slaughters. (Theophylact 8.15.7–8, trans. Whitby and Whitby)
The overthrow of Maurice was the first successful violent deposition of a Roman emperor in the East since Diocletian's coup d'état in 284. Phocas was widely perceived as an illegitimate ruler. Disaffection was aggravated by the religious dissidence of the Monophysite communities of Syria and Egypt, and by rivalry of the circus factions.14
Phocas depended on violent repression of opponents loyal to the old regime. Five of Maurice's sons had been murdered with their father at the time of the coup; his widow, previously confined to a monastery, and daughters were implicated in a broad-based plot and put to death in 605. The bald account in the Chronicon Paschale of the suppression of this supposed conspiracy is an indication of a new brutality which characterized the style of the regime:
In this year in the month of Daisius, June according to the Romans, on a Saturday, there were beheaded Theodore the praetorian prefect, John antigrapheus, Romanus scholasticus, Theodosius subadjutant of the magister, Patricius illustris, nephew of Domnitziolus who was curator of the palace of Hormisdas, John and Tzittas, spatharii and candidati, Athanasius comes largitionum, Andrew illustris who was also called Scombrus, and Elpidius illustris. Elpidius had his tongue cut out and his four extremities removed; he was paraded on a stretcher and carried down to the sea; when his eyes had been gouged out, he was thrown into a skiff and burnt. The other people aforementioned were beheaded, on the grounds that they were discovered plotting against the emperor Phocas. (Chron. Pasch. 605, trans. Whitby and Whitby)
There were serious external setbacks. The Lombards in Italy under King Agilulf forced Smaragdus, the exarch based at Ravenna, to make major territorial concessions in a treaty of 604/5, and in the same year the Avars raised their tribute demands, after Phocas had been forced to move many of his Balkan troops to the eastern front. However, the decisive events which were to topple the regime came from renewed conflict with Persia. Promptly after Phocas' accession, Narses, the magister militum based in Mesopotamia, led a military rebellion in support of Theodosius. Khusro put the full weight of Sassanian power behind him and the eastern frontier crumbled. Dara fell after a siege in 604, the Roman commanders in Armenia offered support to Theodosius, and placed the key east Anatolian fortresses of Theodosiopolis and Citharizon under his and the Persians' control in 607. Mesopotamia and the whole of Asia Minor were thus exposed, and the strongholds soon toppled: Mardin, Amida, Rhesaina, and, in 609, Edessa.
Phocas' authority was fatally undermined by this huge loss of territory, and he faced another internal challenge. In 608 Heraclius, the exarch of Africa based in Carthage, sent a fleet commanded by his nephew Nicetas to seize Alexandria and cut off the Constantinopolitan grain supply. The island of Cyprus was taken, and in September 610 Heraclius' son, also called Heraclius, sailed with a fleet of warships from the sea of Marmara towards the capital. Preparations had been made in the city, and partisans of the Greens opened the harbors to the invaders. Supporters of the rebels already controlled most of the territory and resources of the Levant and Heraclius father and son had for two years issued gold, silver, and bronze coinage, which identified them with the insignia of consuls. This symbolism declared their own standing within the Roman state, while it implicitly denied the legitimacy of the usurper Phocas.15 Phocas was killed on October 5, 610. Heraclius, the son of the exarch of Africa, was proclaimed emperor.
The reign of Heraclius, from 610 to 641, encompassed the last great struggle between the Roman and Sassanian empires, the surrender of Roman control in the Balkans, and the collapse of the empire in the Near East and Egypt. Both the Romans and the Sassanians were confronted and overwhelmed by the growing power of the Arabs united by the religion of Islam. The sources which document these events reflect the complexity of the events themselves. The accounts of this period represent the various regional perspectives in diverse linguistic and historical traditions, a daunting challenge to a classical historian.16 The Roman perspective is represented by the Chronicon Paschale up to 629/30, which focuses on developments in the capital; the chronicle of Theophanes, compiled in the eighth century;17 and the panegyric poems in praise of Heraclius, written by George of Pisidia.18 Theophanes' account derives in part from the detailed accounts by which Heraclius reported on the progress of his campaigns of the 620s. John, bishop of Nikiu, wrote a world chronicle, originally in Greek and written from the viewpoint of an inhabitant of the Egyptian delta, which has reached us through a series of translations and provides an indispensable account of the conquest of Egypt by the Arabs.19 Armenian history, including many observations on the coming of the Arabs, is provided by the work ascribed to Sebeos.20 The Persian version of the collapse of the Sassanian Empire lingers only as transmuted into the epic tales of the Shahnameof Ferdowsi and the great history, written in Arabic, of Tabari, a native of the Caspian region. The fragmentary west Syriac chronicles of the seventh century throw a patchy light on the early Arab conquests of the Levant.21 It has been argued that the surviving eleventh- and thirteenth-century Syriac accounts of Michael the Syrian and of the Chronicle of 1234 (both of which also depend on the ninth-century work of Dionysius of Telmahre), a historical narration written in Arabic by Agapius of Manbidj (Hierapolis) in the mid-tenth century, and the entries of Theophanes, Chronographia, all drew heavily on a common Syriac source, identifiable as the otherwise lost work of Theophilus of Edessa. Theophilus' work, which was completed in the later eighth century, provided a historical account which covered the period of the Roman–Sassanian conflict and the early Arab conquests in the East from c.590–750. An English translation of the sections of the later authors which are clearly derived or adapted from this common source, both defines the scope of Theophilus' work and makes it accessible to a modern readership.22 More complex and difficult than any of these are the earliest Islamic accounts themselves, from a historiographical tradition that bore virtually no relation to classical predecessors.23 Beside the bewildering diversity of the literary sources, there is evidence from archaeology, numismatics, and the documentary record in Egypt, but much work needs to be done in these fields too before a clear picture of the early seventh century is likely to emerge. What follows is intended as no more than a summary and an attempt to highlight the main issues.24
In 609/10 the Sassanian general Shahin invaded Cappadocia and besieged its capital, Caesarea. The city was handed over to the attackers in 611 by its Jewish inhabitants after the Christian population had fled. Meanwhile the main Persian offensive was sustained against Syria. Antioch and Apamea were taken in October 610, Emesa in 611, and Damascus in 613. A Roman counteroffensive led to the recapture of Cappadocian Caesarea in 612. The critical moment for Roman Syria came in 613, when the emperor Heraclius, who had broken with long tradition and led an expeditionary force in person, was defeated by Khusro's forces near Antioch. He withdrew north of the Cilician gates, leaving Cilicia and Syria at the mercy of the Persian general Shahrvaraz. Caesarea Maritima, the Roman administrative capital of the southern Levant, and, traumatically, Jerusalem, fell to the Persians in 614. While the Jews were accused of complicity with the Sassanians, huge numbers of Jerusalem's Christian population were slaughtered or resettled on Persian territory, and the relic of the Cross itself was removed as a trophy to Khusro's treasury at Ctesiphon.25 The gateway to Egypt, Pelusium, was taken in 616 or 617, Alexandria surrendered after a siege in 619, and the Sassanians asserted control along the Nile Valley as far as Syene.26 As was inevitable annona distributions had been suspended in Constantinople since 618 (Chron. Pasch. 618). Thus the whole of the Near East and Egypt was lost to Roman control.
The offensive in the Levant, commanded by Shahrvaraz, was matched by the campaigns of Shahin in Asia Minor, which was overrun from the east for the first time since the incursions of Shapur I in the mid-third century.27 The old inner frontier which stretched from Trapezus through Satala to Melitene was already in Persian hands, and Anatolia could be raided virtually at will. In 615 a Sassanian force under the command of the general Shahin reached Chalcedon, across the waters of the Bosporus from Constantinople. When a desperate plea for peace was brought to Khusro by a high-level legation during the following winter, the ambassadors were simply interned and later put to death (Chron. Pasch. 615). In 617 Persian seaborne forces occupied Cyprus. It appears that most of the overland assaults on Asia Minor were directed, as might be expected, along the Roman road network north of the Taurus, while Roman resistance concentrated in the mountainous regions of the south. As the imperial mints in Cyzicus and Nicomedia ceased production in 616 and 619 respectively, Heraclius struck coins in Seleucian Isauria in 616–17 and in the fastness of Isaura itself in 618. Persian attention turned, as might be expected, to the richest cities, and Ancyra, Sardis, and Ephesus were sacked and plundered. While the immediate impact of warfare was dramatic, and is illustrated by archaeological evidence from these cities, it is less clear that the Sassanians, in the space of less than ten years, could have brought to an end the urban culture of late Roman Asia Minor.28 A broad study of the impact of the Persians throughout the territories that they conquered in the Roman Near East argues that we should distinguish between the brutality and the devastation that they inflicted on centers of Roman resistance, and the much lighter touch with which compliant local populations were handled.29
Roman fortunes reached their lowest ebb in 622. A full-scale Sassanian attack coincided, surely by design, with an onslaught from the Balkans by the Avars. Heraclius, who had taken the field against the Persian army, returned in haste to Constantinople to begin negotiations with the Avars, who may have besieged Thessalonica during this period. In 623 the emperor ventured beyond the protection of the Thracian long walls to seal an agreement with the Avar Chagan, but was almost captured in an ambush, losing much of his entourage. In the crisis one of the emblems of the city's protection, the robe of the Virgin which was kept at the church at Blachernae, outside the Theodosian Walls, was hurried for safe-keeping to St Sophia.30 Humiliating terms had to be agreed with the Avars. Ancyra, the greatest fortress of central Anatolia, was probably captured in 622. In 623, doubtless exploiting the opportunity provided by their new base in Egypt, the Sassanians seized the island of Rhodes and deported many of its inhabitants. Their hands were at the empire's throat.
Events were subject to an extraordinary reversal between 624 and 630.31 Heraclius assembled a field army at Caesarea in Cappadocia, and then marched through northeast Asia Minor into Azerbaijan, through the regions with largely Christian populations which had been under Roman control after 591. Khusro's army, which had mustered at Ganzak, the location of Bahram's defeat in 591, withdrew across the Zagros. Heraclius chose to attack and destroy the fire-temple at Takht-e Suleiman, a formidable fortress which was the symbolic center of Sassanian power in the northwest of the empire, and overwintered with his forces in the valley of the river Kur in Albania. In the following campaigning season he maintained the Roman presence along the southern side of the Caucasus and occupied winter quarters near Lake Van. The Persian riposte came in 626. The two Sassanian generals Shahrvaraz and Shahin led a major counteroffensive, with Shahin advancing through Armenia and Shahrvaraz through the Cilician Gates, both aiming for Constantinople. The plan was coordinated with the Avars, and the Khagan simultaneously led an enormous force against Constantinople from the West. Heraclius blunted the Persian effort by defeating Shahin's forces in Anatolia, and Roman naval forces proved strong enough to prevent Shahrvaraz, who was again encamped at Chalcedon, from crossing the sea of Marmara and joining forces with the Khagan. The Avars, aided by the Slavs, beleaguered Constantinople from the Thracian side in huge numbers through late July and early August 626. The defenders, facing personal annihilation and fighting for the survival of the Roman Empire, forged an unprecedented unity in face of the peril. The icon of their salvation was the robe of the Virgin of Blachernae, and the accounts of the siege raised the cult of the Virgin Mary, and the myth of her protective powers, to an unprecedented prominence.32 The fullest account of the siege, in the Chronicon Paschale, begins with an explicit acknowledgment of the Virgin's role:
It is good to describe how now too the sole most merciful and compassionate God, by the welcome intercession of the undefiled Mother, who is in truth our Lady Mother of God and ever-Virgin Mary, with his mighty hand saved this humble city of his from the utterly godless enemies who encircled it in concert, and redeemed the people who were present within it from the imminent sword, captivity, and most bitter servitude. (Chron. Pasch. 626)
Heraclius participated in the thanksgivings at the capital over the winter of 626 before returning to the offensive in 627. He too made common cause with an ally from the steppes, the western Turkic Khagan, and advanced through Lazica and Iberia to meet these new allies outside the city of Tiflis, which was placed under siege. While the Turks maintained the blockade, the Romans moved south again into Azerbaijan. In December they crossed the Zagros and confronted a large Sassanian army near Nineveh. Heraclius' victory opened the path for the Romans to advance south on Ctesiphon itself. The presence of a victorious and threatening enemy force on the river Zab achieved precisely the same effect as Bahram's mutiny had done in 591. The Sassanian king Khusro II was overthrown and murdered, to be replaced by his son Kavad Siroe who negotiated an armistice and sued for peace. Heraclius returned to Constantinople and a new treaty was struck with the Persians which restored the boundary between the two empires along the frontier which had prevailed before 591, running from Lazica through Theodosiopolis and Citharizon to Dara in Mesopotamia.
Complications followed. Kavad Shiroe himself died in autumn 628 and was succeeded by his young son Ardashir. Meanwhile, most of Syria, Palestine, and Egypt remained in Sassanian hands under the control of Shahrvaraz, who was now based in Alexandria. He entered into negotiations with Heraclius to restore the Near East to Rome, provided that Rome supported his own bid to take power at Ctesiphon. He demanded that the northern frontier section of the empire should now also be shifted westwards to the line of the upper Euphrates. Heraclius, however, achieved a crucial prize, the restitution of the True Cross to Jerusalem. At the beginning of 630 Shahrvaraz entered Ctesiphon, and had Ardashir killed in April. Six weeks later he himself was dead and was succeeded in power by a daughter of Khusro II, who was forced by Heraclius to restore to Rome the Transcaucasian territory occupied between 591 and 602.
The Persian state now imploded into a civil war which saw six short-lived rulers succeed to the throne until the accession of Yazdgird III, the last Sassanian king who ruled between 633 and 651.33 Heraclius meanwhile celebrated his triumph by becoming the first Roman emperor to enter Jerusalem, where he presided over the ceremony of the restoration of the Cross.
Heraclius' success in the last great war with the Persian Empire depended on the Roman ability to transform the nature of their empire at a moment when it was on the verge of disintegration. This transformation took many forms. Heraclius' own route to power, from Africa via Alexandria to Constantinople, which took two years and involved the organization of the resources of Egypt and the Near East against the usurper Phocas, prepared the ground for a new style of rulership. Heraclius himself broke with a tradition more than two centuries old by opting to lead Roman forces on campaign in person. Just as his coup had illustrated the old secret of empire, that emperors might be created elsewhere than at the capital, so his brash campaigning showed that, in moments of extreme crisis, aggression in other critical areas paid greater dividends than relying on survival in fortress Constantinople. His personal style of leadership was linked to strategic adaptability. The emphasis on a cavalry strike force, which had been the hallmark of Roman armies since the fourth century, was reversed. Heraclius' wars were fought by troops in which infantry predominated, as was to be the case with later Byzantine forces. One reason for this may simply have been that it was less expensive and logistically less challenging to maintain infantry armies in the field.
Heraclius and his regime kept their nerve and drew on long experience during the years of crisis. Apart from maintaining a tactical and strategic initiative during the campaigns, they also played their diplomatic cards to good effect. The defense of the Balkans had to be abandoned. The Avars were held in check by tribute payments between 604 and 619, although they controlled all Illyricum west of Serdica and Naissus, which were both sacked around 614. The Sclaveni, whose diffused leadership was less amenable to diplomacy, were a continuous threat in Macedonia, Thessaly, and Greece. Thessalonica survived onslaughts in 604, 615, and 618 thanks to its mighty fortifications, stout local resistance, and the protection of St Demetrius. The Slavs created a primitive fleet of boats made from hollow tree trunks, with which they menaced the Aegean islands and the west coast of Asia Minor, and which almost succeeded in creating a bridge between the Persian and Avar forces at the siege of Constantinople in 626. After this failure the Avar–Slav coalition appears to have fractured, and although Slav colonization of the Balkans continued apace, the power of the Khagan ebbed away. Meanwhile on the eastern front, Rome struck critical new alliances with the Turkic tribes, who were now the most powerful force on the steppes. They were soon to show themselves to be a greater danger to the Sassanians than the Hephthalites had been in the fifth century.