During the first 100 years of Christian history, the church taught some form of millenarianism, or chiliasm (from the Greek word for “1,000”), the belief that the Parousia would bring about a 1,000-year kingdom of fellowship, justice, peace, and abundance here on earth. The coincidence of occasional episodes of millennial exultation and persecution (e.g., about ad 200) suggests the existence of a relationship between apocalyptic expectations and imperial persecutions. Certainly, Revelation viewed martyrdom and millennial promises as two aspects of the same eschatological resolution. But apocalyptic zeal waned because the End never came and the pressure of persecution was intermittent. Moreover, in the aftermath of apocalyptic outbreaks, more responsible and well-connected members of the church pursued a policy of accommodation, insisting that Christians were not hostile to Rome and downplaying both the apocalyptic and millennial dimensions of their tradition. Christian missionaries converted large numbers of Roman citizens, and worldly success and the failure of apocalyptic expectation reduced Christian antagonism toward the empire.

Although millenarian thought lost favour with the clerical elite, it remained popular and appealed to Montanists and other heretics. In characteristic apocalyptic fashion, Montanus, the founder of the movement, was fascinated with the idea of dividing past and future into units of prophetic calculation. In ad 156, according to the 4th-century Christian antiheretical writer Epiphanius, Montanus declared himself the prophet of a third testament, a new age of the Holy Spirit. Phrygia (now in Turkey) became the centre of this movement, whose leaders claimed divine inspiration for their visions and utterances and believed in the imminent descent of the heavenly Jerusalem to the small Phrygian town of Pepuza.

This concept of a third age, the new day of the spirit of God, is one of the most consistently repeated features of millenarian history, reappearing, for example, in Joachim of Fiore’s philosophy of history during the 12th century, in views of the Quakers (Society of Friends) in the 17th century, and in the apocalyptic speculations of the Seventh-day Adventists of the 19th and 20th centuries. In every case, it carries with it an implicit rejection of the contemporary church as an archaic and hierarchical organization that is about to be surpassed.

About ad 200, apocalyptic expectations seem to have reached unusual levels. Montanism spread outside Asia Minor and found converts throughout the Roman Empire, including Tertullian, a North African lawyer and theologian. Apocalyptic prophets, some including bishops, roused their flocks with visions of the imminent End and led them into the desert to meet Christ returning on the clouds. In response to these disastrous errors, a nonapocalyptic version of millennialism, the “sabbatical millennium,” emerged. This argument, recorded about ad 110 in the Epistle of Barnabas, held that because God had created the world in six days and rested on the seventh (Genesis 1) and because 1,000 years is a day in God’s sight (Psalm 89/90), the world must labour 6,000 years before the sabbatical millennium of peace, abundance, and joyful rest for the Lord’s weary would begin. It offered a quiescent alternative to the radical millennialism of the apocalyptic prophets, and it would become more plausible with the passing of each failed apocalyptic episode.

Hippolytus, responding to the irresponsible apocalypticism of his day, connected the sabbatical millennium to a chronology that explicitly dated the arrival of the messianic millennium. By dating Jesus’ Incarnation (God’s assumption of the flesh in the person of Jesus) to 5500 anno mundi (am; Latin: “in the year of the world”—i.e., from the Creation), he could argue in 5700 am (ad 200) that there were still some 300 years left before the Parousia. This tradition was valuable for the same reasons it was dangerous: it reaffirmed millennialism as dogma and offered a concrete date. For at least two centuries, its teachings offered a solution to the problem of apocalyptic millennialism.

The influence of Greek thought upon Christian theology offered church leaders an alternative to the millenarian worldview. The theology of Origen, the great 3rd-century Alexandrian Christian thinker, emphasized the manifestation of the kingdom in the soul of the believer rather than in the world, a significant shift from the historical toward the metaphysical or the spiritual. The association of apocalyptic millenarianism with the Montanist heresy and other troubling antiauthoritarian beliefs and practices discredited it, especially among the clerical supporters of the “monarchical episcopacy” of the 3rd century, who laid the groundwork for the revolutionary notion in Christianity of a sacred empire. This strain of antimillennial political theology climaxed with the conversion of Constantine the Great and the adoption of Christianity as the favoured, and eventually sole, religion of the empire. The theologians of the imperial period either ignored millennial doctrines or in some cases—e.g., Eusebius, Jerome, Ambrose, and Augustine—violently attacked them as carnal, Judaizing, and crude forms of belief.

Traditional historiography holds that as a result of developments, millennialism was discredited for centuries. But millennialism actually survived at two levels. First, it survived among the clergy in the form of a “top-down” millennialism whereby the Christian empire became the fulfillment of the messianic promise. This theocratic identification of the pax romana Christiana (Latin: “peace of the Christian Roman Empire”) with Isaiah’s vision of the peace of the nations (2:1–3) would become one of the most important elements of political Christianity until the end of the Wars of Religion (late 16th century). In the 4th and 5th centuries, imperial Christianity absorbed the messianic symbols of pagan Rome: Rome’s dominion kept the Antichrist at bay (II Thessalonnians 2:3), and Roma aeterna (Latin: “eternal Rome”) became a symbol of the longevity of the new millennial kingdom (just as God rules over all in heaven, so the emperor rules on earth).

Millennialism also survived among the populace that still viewed empire—Christian or not—as the enemy, that still honoured and sought martyrdom, and that emphasized still more insistently the tradition of Revelation. This popular millennialism, best seen in the North African Donatists, periodically emerged at times of apocalyptic expectation, such as the sack of Rome in 410. It probably also inspired many missionaries to spread. Despite having been banished at the highest levels of the clerical elite (who dominate our textual record), millennialism survived in this popular, oral form, especially in the Western, Latin church, until the present.

The year 6000 am grew in significance with each apocalyptic failure. By the 5900s am, however, the millennial chronology would shift from antiapocalyptic to apocalyptic. If, at this point, the chronology bore no connotations of danger for Christians, then they would have greeted the year 6000 with large public commemorations and celebrations, as the Romans did in ad 248 when they reached their 1,000th year. This date carried so much dangerous apocalyptic and millennial freight, however, that the theologians of the Latin West found this millennial chronology unacceptable.