From the fading light of the apostolic and martyr church, the Christian story advances into the era of patriarchs and emperors, when the faith once despised is enthroned alongside imperial power, and the cross is borne not only by confessors in the arena, but by bishops in the council chamber. This third period, stretching from Constantine the Great to Gregory the Great (a.d. 311–590), witnesses the decisive transformation of Christianity’s social position, doctrinal development, and cultural reach—both within the old Graeco-Roman world and among the emerging Germanic peoples on its frontiers.
The New Political and Social Order
The accession of Constantine marks the transition from a persecuted church to an imperial church. The mightiest and most refined paganism known to history—Graeco-Roman idolatry—after three centuries of resistance, surrenders to Christianity. The famous taunt becomes a confession: “Galilean, thou hast conquered.” The imperial successor of Nero and Diocletian now dons the purple not to crush the faithful, but to preside over their councils, even at Nicaea, where bishops, scarred from persecution, sat in judgment under his protection. The once-despised sect assumes the prerogatives of the pagan priesthood, builds churches from the very stones of dismantled temples, and turns the arts and learning of Greece and Rome to the defense of the gospel. It now shapes law, public life, and even imperial policy. Yet with this triumph comes a peril: the influx of unconverted multitudes, bearing with them the habits and ideas of the old world, imposes on the church new temptations and new labors.
The Double Edge of Church–State Alliance
The union of throne and altar breathes both health and harm into every department of church life. The age is marked by a growing worldliness, a waning of apocalyptic expectation, and a new ease in the present order. At the same time, there flourishes an intense counter-movement: the ascetic renunciation of the world, expressed most powerfully in the hermitage and the cloister. Monasticism—sanctioned by such luminaries as Athanasius, Basil, Chrysostom, Augustine, and Jerome—spreads from the Egyptian desert to the farthest reaches of Christendom, offering what many believed to be the surest and shortest path to heaven. Though it sometimes borders on fanaticism, its moral heroism commands popular veneration and shapes the ideal of holiness for centuries to come.
Doctrinal Achievement and Theological Controversy
The Nicene and post-Nicene centuries are second in doctrinal productivity only to the apostolic and Reformation eras. In the East, the Greek church defines the orthodox doctrine of the Trinity and the person of Christ; in the West, the Latin church advances in its understanding of sin and grace. Athanasius, Chrysostom, Jerome, and Augustine tower as the great doctors of this age. Theology becomes a matter of universal interest: emperors, artisans, and the populace alike are drawn into the passionate disputes that lead to the formulation of the ecumenical creeds. Yet this very definiteness narrows the bounds of permissible inquiry. Divergence from the state-endorsed creed is now punished not only by ecclesiastical censure but by imperial sanction—a practice which, once begun, will darken the Middle Ages and echo into modernity.
Hierarchy and Organization
Ecclesiastical structure adapts itself to the imperial framework. Bishops become prominent public figures, sometimes at the expense of spiritual independence, especially within the Byzantine court. The episcopal system develops into metropolitan and patriarchal hierarchies. By the fifth century, the five great patriarchates—Rome, Constantinople, Antioch, Alexandria, and Jerusalem—stand at the summit of church governance, with Rome and Constantinople as the principal rivals. The Roman bishop already asserts claims to universal jurisdiction, foreshadowing the medieval papacy.
Worship and Religious Culture
Christian worship, enriched by art and architecture, gains in beauty and grandeur. Sacred buildings rise; music, sculpture, and painting serve the liturgy; poetry finds a home in the hymn. Religious festivals multiply, sometimes merging with lingering pagan sensibilities in the veneration of saints and martyrs. Rituals grow in number and splendor, often captivating the senses but risking the loss of simplicity and spiritual fervor. Alongside this ceremonial richness, the beginnings of a reaction can be discerned among those who long for a purer, more inward devotion.
Continuity and Transformation
Despite the outward transformation brought by Constantine’s favor, this period is the natural continuation of the pre-Constantinian church—its strengths and weaknesses both magnified in a new environment. By the end of the era, attention must turn not only to the Roman world but to the Germanic tribes pressing in from the north and east. Christianity will outlast the political collapse of the Western Empire in 476, and, in time, convert its conquerors, teaching them the arts of peace and laying the foundations for a new Christian civilization on the ruins of antiquity.
Subdivisions of the Period
1. The Constantinian and Athanasian Age (311–381): From Constantine’s conversion to the Second Ecumenical Council, dominated by the Trinitarian controversies with Arianism and semi-Arianism.
2. The Post-Nicene or Christological and Augustinian Age (381–451): Theological focus shifts to the person of Christ (Nestorian and Eutychian controversies) and to the doctrines of sin and grace (Pelagian controversy).
3. The Age of Leo the Great (440–461): The rise of papal primacy in the West amidst barbarian invasions and the fall of the Western Empire (476).
4. The Justinian Age (527–565): The Byzantine state-church system reaches its zenith and begins its decline.
5. The Gregorian Age (590–604): Transition from the ancient Graeco-Roman to the medieval Romano-Germanic church, preparing the way for the Middle Ages.
