Constantinian Refoundation and the Invention of the Christian Roman State

Constantinian Refoundation and the Invention of the Christian Roman State

The Constitutional Problem: From Persecutor to Patron

The historiographical question of Constantine's "conversion" has traditionally been posed in biographical and psychological registers, as though the answer lay in recovering the interior spiritual experience of a single ruler. This framing, inherited from Eusebius's *Vita Constantini* and amplified by Gibbon's ironical skepticism, obscures the more consequential question: how did a constitutional settlement produced in the legal aftermath of the Great Persecution establish a model of sacralized Christian monarchy whose institutional logic outlasted every subsequent dynasty and continued to define Byzantine governance until 1453? The Edict of Milan (313), the foundation of Constantinople (330), and the convocation of Nicaea (325) are not discrete events to be evaluated individually against the standard of personal piety; they constitute a single, if unevenly executed, refoundational project whose architectural grammar—the fusion of imperial cult with Trinitarian orthodoxy, the topotheological re-inscription of civic space, the instrumentalization of episcopal authority, and the repurposing of Tetrarchic administrative structures—generated the constitutive tensions of Byzantine political-religious culture.

This chapter argues that the Constantinian turn is misread if treated as a rupture. It was, rather, a strategic synthesis in which the emperor assumed a sacerdotal-pastoral role without precedent in Roman constitutional theory, drawing on the inherited vocabulary of the *imperator* as cosmic mediator while recharging it with biblical typology and ecclesial language. The result was neither a Christian theocracy in the medieval western sense nor the late antique equivalent of a secular state; it was a hybrid configuration in which doctrinal orthodoxy became a matter of imperial administrative concern, the bishop acquired quasi-magisterial dignity within his civitas, and the emperor himself functioned as a kind of external bishop whose decisions in matters of faith bound the Christian oikoumene. The chapter proceeds by examining (1) the legal-religious architecture inaugurated by Milan, (2) the Donation as both contested document and operative ideology, (3) the topotheological construction of Constantinople, (4) the Nicaean settlement as the inaugural instance of doctrinally inflected imperial policy, (5) Eusebian political theology as the discourse within which the new synthesis became intelligible to its first audiences, and (6) the institutional continuities with the Tetrarchy that made the new content administratively viable.

A preliminary methodological caution is necessary. The very term "Constantinian" should be used as a historians' shorthand for a constellation of initiatives spread over three decades (313–337) and produced by a court apparatus whose internal divisions are increasingly visible in recent scholarship. Cameron, Drake, Van Dam, and (most trenchantly) David Potter have shown that the narrative of a single willed program obscures contestation, pragmatism, and regional variation. Yet the abbreviation retains analytical utility, provided one specifies that what is meant is not Constantine's biography but a structural pattern of imperial-religious articulation that crystallized in his reign and conditioned every subsequent response, from Julian's attempted rollback through the Theodosian establishment of trinitarian orthodoxy as compulsory to the iconoclast councils of the eighth and ninth centuries.

The Edict of Milan and the Birth of Imperial Religious Neutrality

The Edict of Milan is best understood not as a charter of religious liberty in the modern sense but as a constitutional compromise between two imperial co-Augusti—Constantine and Licinius—formulated to resolve the legal status of Christian communities that had been dispossessed during the Diocletianic persecution (303–311). The text preserved by Lactantius (*De mortibus persecutorum* 48) and embedded in Eusebius's *Ecclesiastical History* (X.5) is short, juridical, and concerned less with abstract rights than with the restoration of property and the conferral of juridical standing upon Christian corporate bodies. Its famous clause—that "the supreme divinity" (*summa divinitas*, or in Eusebius's version, "the supreme god") may be worshiped freely by Christians and by all others—formulated religious permissiveness as a function of the *concordia* that the restored tetrarchic concord required. It was, in this sense, a Galerian policy extended and refined: the Edict of Nicomedia (311) had already conceded the right of Christians to exist and to rebuild their places of worship, provided they prayed for the safety of the emperor and the state; Milan universalized the formula.

Three features of the edict require emphasis for understanding the post-Constantinian constitutional order. First, it operated within, and did not abolish, the inherited Roman category of *religio* as a public and politically consequential affair. Religious practices, including Christianity, were recognized as legitimate activities of corporate groups (*conventicula*, *ecclesiae*) whose liberty was now protected by imperial rescript. This protection was not predicated on a doctrine of individual conscience but on the prudential calculation that the gods—including, by deliberate ambiguity, the Christian god—required appeasement through the orderly conduct of cult. The edict thus inaugurated what one might call "imperial religious neutrality," a posture distinct both from the earlier claim of the *pontifex maximus* to direct the religious life of the Roman people and from the later Theodosian identification of orthodoxy with public order. It was the first of the three Constantinian coordinates: legal recognition without doctrinal enforcement.

Second, the edict implicitly created a new kind of legal person. Christian communities, which had previously operated as private associations (*collegia*) of doubtful standing under the *lex Iulia de collegiis*, were now constituted as legitimate corporate bodies with proprietary rights and an institutional existence independent of their members. This is the constitutional foundation for the later imperial episcopate's claim to juridical personality—a claim that would become immensely important when Constantine summoned bishops to act as arbiters in intracommunal disputes and authorized them to exercise a kind of compulsory jurisdiction. The edict did not establish ecclesiastical courts; it established the legal conditions under which episcopal *episteme* and *synallagma* (as Constantine would later designate them in a rescript of 318) could acquire the force of binding arbitration backed by imperial sanction.

Third, the edict's pluralist formula had a half-life considerably shorter than its rhetorical afterlife in Enlightenment polemic would suggest. Within a decade, Constantine's correspondence with bishops and his interventions in the Donatist and Arian controversies revealed that the language of "supreme divinity" could not, in practice, sustain the neutrality it proclaimed. The emperor would come to identify the Christian god with the supreme deity and Christianity with the cult most pleasing to him. The Eusebian vocabulary of the *Tricennial Oration* (336) treats the favor of the Logos as the explanation of imperial success, and the Eusebian *Vita Constantini* presents the empire as a kind of cosmic-liturgical enterprise whose telos is the worship of the one true god through his imperial image. The Milanite neutralism was, in this sense, the founding compromise whose preservation in the western tradition as a "charter of Christian liberty" is itself a historically interested reading. In the Byzantine East, the alternative Eusebian reading predominated: religious liberty was a stage in the progressive divine pedagogy that cu