To delay the End and reap the benefits of nonapocalyptic millennialism, theologians placed great weight on the idea of a “sabbatical” millennium. Combining Genesis 1 (six days of travail, then one of sabbath, or rest) with Psalm 90 (1,000 years equals a day in the sight of the Lord), this concept promised the advent of the 1,000-year kingdom after 6,000 years. About ad 200 the first Christian chronology placed the Incarnation (God’s assumption of the flesh in the person of Jesus) in anno mundi 5500, the anno mundi [am; Latin: "in the year of the world"] chronology beginning at the creation of the world according to the Hebrew scriptures. As a result, the year 6000 am was still 300 years in the future, in what would become ad 500. When apocalyptic prophets announced the imminent End, conservative clerics countered that centuries remained until the millennium. Documentary evidence of this chronological argument suggests the presence of popular apocalyptic rumours at this time, because contemporary theologians would have used the argument to calm the anxiety such rumours incited. Of course, such chronological temporizing merely postponed the millennium (eventually the 6,000 years would pass); it also fostered apocalyptic millennialism as the prescribed Endtime approached.
While trying to postpone millennial hopes, theologians also attempted to eliminate Christian millennial hostility toward the Roman Empire. Central to these attempts was a new interpretation of St. Paul’s discussion of the timing of the End and his reference to an “obstacle” to the advent of the “man of iniquity” in 2 Thessalonians. According to this interpretation, the Roman Empire provided the obstacle for this Antichrist. After Christianity became imperial, this pro-Roman eschatology would produce the myth of the Last Emperor, a superhuman figure who would unite all of Christendom, rule in peace and justice for 120 years, and abdicate his throne prior to the brief rule of the Antichrist. Imperial millennialism probably influenced Constantine I—the first “Last Emperor”—and offered a powerful antidote to the subversive elements of popular millennialism. Its cosmic struggle was not earlier Christianity’s contest between holy anarchy and an evil human empire but a contest between an authoritarian holy empire and anarchic chaos. Not surprisingly, this “top-down” form of millennialism found much favour among later Christian theologians. Patristic and medieval millennialism
However creative or successful with theologians these approaches were, they merely delayed the problem. Despite pagan and Christian belief in Roma aeterna (“eternal Rome”), the empire would fall. No matter how far away 6000 am (ad 500) seemed from 5700 (200), it did not seem so far away in the 5900s (400s). Indeed, the Western Roman Empire faltered just as the year 6000 approached, turning the antiapocalyptic sabbatical chronology and imperial “obstacle” to Antichrist exegeses into profoundly apocalyptic ones. At the beginning of the 5th century ad (c. 5900 am), Jerome and Augustine, perceiving the danger of apocalyptic millennialism, developed new and more stringent ways to oppose to it. Jerome introduced a new set of calculations (am II) that placed the Incarnation roughly 300 years earlier, thus allowing Latin chronographers to ignore the advent of the year 6000 am I. At the same time, he heaped ridicule and contempt on millennialists, the believers in foolish tales of earthly delights, gluttony, and sexual promiscuity.
Augustine went still further, arguing that neither history nor chronology can be interpreted apocalyptically and that the millennium was not a future event but one that already had been set in motion by Christ. To explain the continued existence of war, hatred, injustice, and poverty, Augustine used the notion of the “Two Cities.” There was a “heavenly city,” the celestial Jerusalem where the millennium was already manifest, and an “earthly city,” the terrestrial Babylon where the millennium was not visible. These two cities would coexist as a corpus permixtum (“mixed body”) in every man and in every society until the end of time. Thus the empire and the earthly church could not represent the perfection of eschatological fulfillment, and their historical fate had nothing to do with God’s plans for human salvation. This interpretation radically reoriented Christian eschatology and eliminated from Christian theology the belief in a coming kingdom of God on earth.
This ban on millennial thought so dominated the “official” theological writings of the early Middle Ages that most modern historians think that it had disappeared entirely from Latin Christendom. Certainly, standard treatments of millennialism tend to jump from Augustine in the 5th century ad to Joachim of Fiore in the 12th century ad, when the first formal theology that anticipated the millennium reemerged. There also were signs of millennialism, however, in the activity of antiecclesiastical prophets such as the "False Christ” of Bourges, described by Gregory of Tours in Ten Books of Histories, and in the antiapocalyptic chronology used to oppose them. Gregory, for example, published his chronology for "those who despair at the coming end of the world." Writing in the late 5700s am II (6th century ad), he and his colleagues repudiated the legitimacy of the “saints” who emerged after the assassination of the “False Christ” by arguing that the millennium was still more than two centuries away. Of course, even this more remote date eventually drew near, and in the 8th century ad (the 5900s am II) the English monk Bede and his Carolingian followers did for am II what Jerome had done for am I: they shifted the dating system again, this time to anno Domini (ad; “in the year of the Lord”). Consequently, millennial implications were once again shrouded by a new dating system; the year 6000 am II became ad 800.
However, the relative silence in extant documentation does not mean that there was no further discussion of the approaching year 6000. Indeed, as with 6000 am I (ad 500), the approach of 6000 am II brought an acute political crisis—the “obstacle” of 2 Thessalonians had been removed, because the Byzantine (Roman) throne was occupied by a woman, Irene, and thus was technically vacant. Charlemagne’s response, to hold his imperial coronation on Christmas Day, the first day of the new year 801, of the year 6000 am II (ad 800, according to the modern calendar, which starts the new year on January 1), unquestionably held millennial significance, despite the reluctance of the written sources to elaborate. The coronation was, in this sense, like the "emperor’s new clothes": everyone in the court knew of the am II equivalent of the date, but no chronicler mentioned it. Ignorant of this significance, modern historians have analyzed this pivotal moment in Western history without any awareness of its millennial background.
Pope Leo III crowning Charlemagne emperor, miniature in the Grandes Chroniques de France, manuscript illuminated by Jean Fouquet, 1460; in the Bibliothèque Nationale de France, Paris (MS. fr. 6465).Courtesy of the Bibliothèque Nationale, Paris
Charlemagne’s coronation contributed two essential elements to subsequent European millennialism. First, he "transferred" the empire, with all its apocalyptic and millennial freight, to the West, including the notion of the Last Emperor and the idea that the Carolingians were the new “obstacle” to the Antichrist. Numerous European kings claimed this messianic status, but the German emperors—particularly Otto III, Frederick I (Frederick Barbarossa), and Frederick II—proved especially fascinated by the idea of the Last Emperor. Second, the Carolingians shifted chronological hopes for the apocalypse from 6000 am II (ad 800) to ad 1000, a date at once millennial (the end of the sixth age, dawn of the Sabbatical era) and Augustinian (the end of the millennium begun by the Incarnation). Unlike with previous revisions of millennial dates, chronographers were unable to shift the chronology without mentioning the apocalyptic date.