In the sixth century, imperial armies were still large, the infantry tactics and military units of Rome’s heyday were still in use, and they functioned on the strength of an urban economy whose structure was older still (see below, pp. 99–100). Expeditionary forces reconquered the coastline of north Africa and southern Spain and took back Sicily and Italy; their spoils bolstered Justinian’s (527–65) triumphalist claim to have restored the Roman empire to former worldwide glories (see below, pp. 201–3, 207, 208–10). Yet these were protestations in the face of uncertainties arising from plague, natural disasters, incursions of armed outsiders and internal religious dissent. Characteristics of Byzantium following the seventh-century ‘transformation of a culture’19 can already be discerned in the era of Justinian – notably the fusion of faith and imperium; penny-pinching and a cast of defensiveness behind imperial bluster; and the assumption that a correct approach to the divine held the key to earthly imperial as well as spiritual salvation. The uncertainties of the sixth century made divine sense, if one accepted the numerous predictions of the end of the world then in circulation.20 While individual responses ranged from the traditional to the Christian, involving amulets, relics and incantations,21 church-going congregations and monasteries looked to the scriptures, priest-directed worship and holy men. In enumerating the fortified towns and refuges furnished by Justinian for rural populations in the Balkans, Procopius acknowledged the inevitability of barbarian incursions: yet he also stressed that the emperor was manifestly doing everything within his powers to protect, offering his subjects both a literal and spiritual safe haven (see below, p. 111).22 Thus the imperial order joined forces with faith and public acts of worship to offer a modicum of security: it is likely that by the later sixth century, images of the Mother of God and of the saints were being venerated with mounting intensity and orchestration.23 The emperor also offered underpinnings for social peace and order in the form of clear, accessible codification and distillation of Roman law (see below, pp. 107–9). A peculiar blend of military triumphalism, strenuous intercession for divine support and careful husbanding of assets helped the Byzantines survive as a collective the drastic turn of events in the seventh century and beyond. The medieval empire’s components were scattered and disparate, from the basileus in his God-protected City down to the inhabitants of fortified towns and self-sufficient, semi-pastoral hill-country kingroups in Anatolia or the Balkans. Their material circumstances and degrees of security varied considerably. But a substantial proportion even of the country-dwellers were within reach of refuges of some kind, and also of churches. Since the blend began to be brewed in Justinian’s era – when elaborate earthly measures of protection for the civilian population were instituted, first put constantly to the test and found only partly wanting – so do our opening chapters. They also take full account of the empire’s eastern neighbours and rivals, current and to come. Persia’s rulers, the Sasanians, made much of their victories over the Romans, defining their own power in terms of these. Yet their institutional base may not have been quite as firm as this implies, while substantial minority groups within their realm worshipped the Christian God (see below, pp. 144, 153–5). The coexistence and cultural interaction of these two great powers prefigures that of Byzantium and the Abbasid caliphate, whose court in Baghdad drew on Persian customs, political thought and high culture.24 The Arabs in the age of the Prophet Muhammad lacked the Persians’ sophistication, yet their capacity for literacy, diplomacy and organised warfare was more advanced than hostile Romans, or their own later writers, allowed. To that extent their adroitness in exploiting the aftermath of ‘the last great war of antiquity’ between Byzantium and Persia is perhaps unsurprising (see below, pp. 174, 193–5). By the seventh century, the Armenians had long been Christian. The inventor of their distinctive script,Mashtots‘, based it on the Greek alphabetical model.He had received a Greek education, and Christian Armenia’s literary culture drew heavily on the fourth-century Greek fathers as well as Syriac writings (see below, p. 161). But the Armenians had their own church hierarchy, headed by a catholicos, and the princely and noble families in mountain strongholds debarred Romans and Sasanians alike from outright control over their respective sectors in Caucasia. For Justinian and his successors, the Armenian church posed a conundrum as intractable as was the papacy to their west: Christian, notionally beneath their umbrella, and yet highly articulate and prepared to defy the emperor and his senior churchmen on matters of doctrine (see below, pp. 171–2). The Armenians stood in the way of the idea of a Christian church coterminous with the empire even as, individually and collectively, they made an extraordinary contribution to its workings.25 Justinian’s legacy was, then, a singular concoction in unpredictable circumstances. Its supreme and understated asset was flexibility, the capability to withstand military setbacks through a blend of material safeguards, ad hoc diplomacy, spiritual purity, ideological vision – and bluff. The ‘beacon’ was not only St Sophia but Constantinople itself, where law and order were upheld and where the unceasing rites of empire and worship were performed, shielded by imperial orthodoxy (see below, pp. 111–12, 114). The emperor as beacon-keeper could still convincingly take charge of these essentials, although in reality he was unable to direct the course of events in all his provinces. Justinian’s reign can therefore be seen as prologue and scene-setter for all that was to come, until the City of Constantinople actually did fall to barbarians, albeit fellowChristians, in 1204. In many ways the sixth century was the starting-point of the cycles of rebuffs and recoveries that characterised the middle Byzantine period. An alternative starting-point for our story might indeed have been the sensational events of the mid-seventh century. The chapters belowsubscribe to the widely held view that the eastern empire underwent massive shocks in the seventh century: thereafter things were never quite the same again, for all the restoration of order in many provinces and the semblance of Roman continuity maintained in the capital. The Arabs’ overrunning of the Levant and Egypt halted inflows to Constantinople of taxes and resources from what had been by far the richest provinces of the empire, dislocated distribution networks and military funding, and in the words of a mid-seventh-century text left the empire ‘humiliated’.26 Few, if any, men of letters could see the point of celebrating imperial deeds in the guise of classical heroics. Grand historical narratives in the mould of Thucydides, such as Procopius’ or Theophylact Simocatta’s, and rhetorical poems such as George of Pisidia’s in praise of Heraclius’ campaigns against the Persians in the 620s, could scarcely be cast from collapsing frontiers and incessant improvisation. As Averil Cameron has pointed out, much was still written, but with regard to the world of the spirit and the transcendent meaning of things, sermons, theological tracts and disputations.27 The lights go out, so far as straightforward narrative is concerned, and our main surviving Byzantine accounts of events from around 640 onwards were not composed before the early ninth century. Yet this change in source-materials does not necessarily imply a corresponding rupture in every single aspect of governance or of spiritual priorities for all the inhabitants of the empire at that time. The differences in civil administration and military organisation which are clear from our sources for the ninth century cannot be dated precisely, and few scholars now subscribe to George Ostrogorsky’s thesis that systematic military reforms and creation of a theme system were carried out by Heraclius in immediate response to the Arab invasions (see below, pp. 239–40, 266). The shifts of overall responsibilities to military commanders (strat¯egoi) and their staffs in the provinces may well have been provisional and fluctuating, with independent civilian authorities still functioning through the eighth century. The sixth and seventh centuries show sufficiently similar administrative arrangements still in place and important processes of change continuously underway to be viewed together in one part. Moreover, as Andrew Louth shows in Chapter 4, disputes about doctrine went on being fought out by churchmen under the emperor’s eye in the mid-seventh century and an ecumenical council was convened in his City reaches, the Danube continued to act as barrier, if not formal border, until the Bulgars installed themselves south of the river in the early 680s; and Carthage, an imperial administrative centre and strategic key to the central Mediterranean, only fell to the Arabs in 698. Until around that time, imperial statesmen may well have reckoned that the Arabs’ extraordinary advances would eventually be repulsed, or would ebb away. It therefore seems defensible to bracket the seventh century together with the sixth as the time when the Christian empire first demonstrated its capacity to go through massive earthly vicissitudes, military triumphs and sudden reversals. For all the sense of imperial Roman continuity that Justinian’s propaganda conjured up, his genius lay in providing for conditions of incessant change.