From about ad 400 onward, Augustine attacked not only the popular, anarchistic variety of millennialism that his fellow Church Fathers reviled but also the hierarchical, authoritarian kind that Eusebius and others so ardently embraced. He did so by presenting history as operating in two different realms—the heavenly and the terrestrial. The heavenly city, the expression of spiritual perfection and union with God, was not visible to those still in the terrestrial city, where good and evil continued to coexist in a single body. Millennial perfection could not be achieved in this world. Only at God’s promised climax to history, at the very end of the terrestrial world of time and space, would good and evil be separated. Until that unknowable time, humanity lived in the saeculum (Latin: “age”), an opaque world of time and space in which humans could not know anything about the End—not when it would happen, not how it would happen, not who would be saved.

This theology of history, adopted from the Donatist theologian Tyconius, offered Augustine a means to attack both of eschatology’s most troublesome aspects. He could refute the notion that the signs of the End can be “read” in the people and events of history (e.g., the Goths and Visigoths as Gog and Magog). He could also remove Christianity from its theocratic identity with the Roman Empire—no earthly institution could be “pure” in the terrestrial city. (This was a particularly important argument to make after the sack of Rome in 410, when, at least in its Western region, many believed that the empire had collapsed). At the same time, he could decouple millennialism from future expectations because the millennium was not a future time of perfect peace on earth but rather a time already begun—with the establishment of the church—a time of perfect peace in the heavenly city. This stupendous exegetical achievement would dominate ecclesiastical commentaries on Revelation for the next eight centuries and most formal theological discourse through the Reformation.

In response to the prevalent this-worldly apocalypticism of his contemporaries, Augustine developed an eschatology that seemed almost oblivious of time. Indeed, his notion of saeculum (whence comes the English word secular) radically desanctified history, presaging modern thought on time by almost 1,500 years. Augustine anticipated no imminent supernatural intervention in history. His immanent, or “realized,” millennium at once acknowledged and embraced history, but it also argued that the battle that really mattered had already been fought on the spiritual plane, where God had triumphed. Satan has been reduced to lordship in this world. The City of the World and the City of God had been forced to coexist. Eventually, even that “small” patrimony that Satan claimed would be taken from him, and God would triumph.

The grandeur, depth, and subtlety of Augustine’s vision has long inspired readers. His refusal to panic at Alaric’s sack of the “Eternal City” in 410 and, like others, shout the news of its apocalyptic “fall,” and his understanding of a sacred and secular universe that could endure even the collapse of empire, earned him an extraordinarily high reputation among theologians and scholars. But we cannot be as certain of the contemporary success of his work. Part of what makes Augustine so compelling to every succeeding generation is that he was right and the apocalyptic prophets were wrong: the world did not end. Augustine’s historiographical millennialism continues to inspire people with its rigorous agnosticism about where history meets its end. Humankind just cannot know. According to this Augustinian approach, we must be prepared at all times, but we must not abandon our daily tasks. As both Jewish and Christian antiapocalyptic lore holds: “If word comes that the messiah has arrived, go on planting trees.”

But these are theological issues, and historians have yet to explore the historical question, How convincing was Augustine to his contemporaries? His debate with the openly apocalyptic Dalmatian bishop Hesychius in 418–419 indicates that ecclesiastical leaders, almost a decade after Rome’s sack, remained intensely apocalyptic in their reading of contemporary history. Thus, Augustine may not provide the best measure for gauging the attitudes that characterized the late Roman Empire, an age in which some bishops believed that their vocation was to “nourish their flocks” with apocalyptic fervour and who viewed the collapse of the Roman Empire as an apocalyptic event.

Despite his austere apocalyptic agnosticism, Augustine threw his support behind a new chronology that put the year 6000 am off for another three centuries. By his day, the approach of the year 6000, according to Hippolytus’s reckoning, supported the apocalyptic arguments that the earlier chronology had been introduced to refute. Indeed, Augustine points to people who, almost a century too soon, associated the fall of Rome (5910) with the advent of 6000. The new calculations, anno mundi II, first proposed by Eusebius in ad 303, rejuvenated the world by some three centuries: the Incarnation occurred not in 5500 am but in 5199, and thus the year 6000 would come in ad 801 rather than 500.

The new chronology of the sabbatical millennium, am II permitted Christians to refer to the calendar without being constantly reminded of the approaching year 6000. This new chronology also offered the same repudiation of apocalyptic fervour that am I had some two centuries earlier. Thus, Augustine could use it to refute the apocalyptic significance of Rome’s fall. Like his Tyconian reading of Revelation, Augustine’s acceptance of the new, nonapocalyptic chronology of am II dominated the writing of theologians.

This shift in chronologies, however, did not happen in the Greek church, whose theological leaders prepared to confront the potential disruptions of the approaching year 6000. The theocratic elements of Christianity developed more solidly in the empire of Constantinople, which was able to sustain a viable political structure even as the Western Empire was collapsing. Thus, imperial millennialism, fortified with imperial prophetic literature, dominated political thought more effectively than in the West. There were particularly strong assertions of imperial millennialism about 6000 am (ad 500) with the emergence of the legend of a “Last Emperor,” a supernatural messiah figure who, it was believed, would rule the world in peace and unity—from once and future messiah to once and future king.

The year ad 500 therefore marks a crucial turning point in the history of millennialism. It was the moment of the victory of imperial millennialism in the East (Byzantine Empire) over the popular, anti-imperial beliefs of the sabbatical millennium, and it was the moment of the victory of popular millennialism in the West over the efforts to link Christianity’s messianism to the new Germanic kingship that replaced imperial authority.

At approximately the same time, a fundamental shift in the locus of the sacred occurred in the East and West. In the East, holiness could inhabit the living: ascetics like the stylites could occupy the liminal space between the corrupt world and the pure one. Like the royal prophets of biblical times, these men would not challenge the hierarchy; they merely chastized its abuse of power. In the West, however, the only good saint was a dead saint, and the locus of “clean power” resided in the relics (the physical remains of the saints, often venerated by Christians). The survival of anti-imperial millennialism in the West often was manifested in radical opposition to the church, a threat as great as acknowledgement of the year 6000. Similarly, the relic cults, whose theology Augustine virtually launched in the last book of the City of God, may have been a popular form of his two-tiered millennium—the relics of the saints offered the faithful on earth a vision of the heavenly city. The immense popularity of relics in the early Middle Ages seems closely linked to ecclesiastically approved manifestations of apocalyptic ardour.