Christ the Emperor: Christian Theology and the Roman Emperor in the Fourth Century AD

Nathan Israel Smolin, Christ the Emperor: Christian Theology and the Roman Emperor in the Fourth Century AD, Oxford Studies in Late Antiquity (Oxford: Oxford University Press, 2024). 9780197689547.

Reviewed by Leslie Ivings, independent scholar, ivingsl188@gmail.com.

The transformation of the Roman Empire in the fourth century CE was not merely institutional or territorial, it was intellectual, symbolic, and theological. As emperors from Constantine to Theodosius I grappled with the implications of Christianity’s new role in imperial life, so too did bishops and theologians reckon with what it meant to imagine divine and earthly sovereignty together. In Christ the Emperor, Nathan Israel Smolin offers a major new study of how the language of imperial authority did not vanish in this period of doctrinal upheaval but rather migrated into Christian theology where it shaped debates about hierarchy, unity, and legitimacy. At once rigorous and ambitious, the book seeks to reposition the political theology of the later Roman world not as an appendix to imperial or ecclesiastical history but as a formative space in which imperial and theological discourses intertwined, which would later end up shaping such concepts as the divine right of kings during the Medieval and Renaissance periods in Europe.

Smolin’s central thesis is that in the fourth century, Christian theology served as a vehicle for imperial political thought, particularly after Constantine’s ascent and the ensuing crises of legitimacy that came with intra-Christian division. In the absence of clear constitutional mechanisms, Smolin argues, imperial authority required symbolic legitimation, first through traditional Roman channels and later through theological ones. The result is a portrait of Roman Christianity not merely as a religion of personal salvation or doctrinal dispute but as a discursive system capable of sustaining imperial power. The argument is carried out with sophistication, engaging both political history and patristic literature in equal measure.

The book is divided into two main parts. The first half (Chapters 1–4) examines the reigns of Constantine and Constantius II, with particular emphasis on the self-presentation of Constantine as a divinely chosen ruler and on Eusebius of Caesarea’s political theology. In Smolin’s analysis, Eusebius does not simply sacralise imperial monarchy, he constructs a model of cosmic governance with Christ as the heavenly emperor and Constantine as his earthly image which would resonate for more than a millennium after being developed. Drawing upon a rich trove of panegyrics, letters, and theological treatises, Smolin describes how Constantine became a “cosmic emperor,” ruling not just by force or law but as the terrestrial analogue of the divine Logos. In the Eusebian schema, hierarchy is sacred, unity is paramount, and imperial power is not only legitimate but is manifestly necessary.

Chapter 3 stands out for its engagement with multiple levels of discourse. Smolin distinguishes between rhetorical, cosmic, and metaphysical registers of imperial ideology, noting that theological arguments about the Trinity or Christ’s nature often bore unspoken parallels to concerns about succession, unity, and hierarchy in the imperial state. This tripartite framework helps the reader understand why otherwise abstract theological quarrels carried such political weight: they functioned as mirrors to the imperial order.

The second part of the book (Chapters 5–6 and an epilogue) turns to Western Nicene authors, and in particular, Lucifer of Cagliari and Hilary of Poitiers. These figures, marginalized in traditional ecclesiastical histories, emerge in Smolin’s telling as key contributors to a new political theology. Opposed to Arian subordinationism and sceptical of the emperor’s spiritual authority, they articulated a vision in which bishops, not emperors, became the guarantors of orthodoxy. Their theological commitment to consubstantiality in the Trinity thus came with political implications: the rejection of imperial mediation in matters of faith and the redefinition of legitimacy as rooted in episcopal, rather than imperial, sanction.

This is one of Smolin’s most illuminating contributions as he shows that Western Nicene theology reimagined the structure of ecclesial and political power, placing the bishop, now understood as a Christian figure of unity and truth, in the place once occupied by the emperor. In tracing this shift, he anticipates the eventual Theodosian synthesis, in which imperial power is once more aligned with Nicene orthodoxy, but on new terms where the emperor is the Christian sovereign, but the church is the arbiter of doctrinal legitimacy.

The book ends with an epilogue that brings the argument into conversation with Theodosius I’s reign, suggesting that the settlement of Nicene orthodoxy under Theodosius drew heavily upon the intellectual groundwork laid by earlier theological polemicists. It was not inevitable that the empire would become Nicene. It was the result of long struggles that were political and doctrinal, personal and imperial, mediated by a shared vocabulary of unity, legitimacy, and cosmic hierarchy.

Smolin’s work builds upon but also challenges earlier traditions of scholarship. He is clearly in dialogue with Erik Peterson’s 1935 classic Monotheism as a Political Problem, which argued that the monarchical conception of God was structurally incompatible with democratic or pluralist governance. Smolin accepts Peterson’s insight that theological ideas are political but challenges his pessimism. In the fourth-century context, he argues, monotheistic metaphors provided the only available framework for legitimizing imperial unity, especially in the wake of repeated civil wars, usurpations, and theological schisms. He also distances himself from older narratives of Edward Gibbon, who tended to dismiss fourth-century theology as empty casuistry or a distraction from the real business of government. For Smolin, theology was the business of government, or at least of imperial ideology.

Methodologically, the book is rigorous. Smolin is a sensitive reader of texts, and his engagement with primary sources, especially Eusebius, Hilary, and Lucifer, is both close and conceptually rich. He pays careful attention to terminology, translation, and historical context, and rarely forces an argument where the evidence is thin. His use of Greek and Latin sources is judicious and the reader is rarely left wondering how he arrives at his conclusions. Moreover, he writes with clarity and force, avoiding jargon without sacrificing precision.

That said, there are limitations. The book’s focus on major authors and figures like Constantine, Eusebius, Constantius, Hilary, and Lucifer means that other figures, including Ambrose, Damasus, and John Chrysostom, are only briefly mentioned or excluded. Smolin explains this as a deliberate focus on the fourth-century formative phase, but one wonders whether greater integration of Western episcopal voices in the 370s–390s might have complicated or enriched his narrative. Likewise, the emphasis on textual sources means that material culture such as coins, inscriptions, and architecture is largely absent. This is a missed opportunity, since presentation of the imperial image was not merely verbal but visual and performative. In an age of gold medallions and monumental statuary, the cosmic emperor was as much a spectacle as a theological concept.

There are also points where Smolin seems to overstate the intentionality of theological political theory. While his claim that bishops were articulating models of power through theology is compelling, one might question whether all such arguments were consciously political. Much of theological discourse is deeply personal, devotional, and speculative. Smolin’s framing sometimes risks instrumentalizing it by reading all doctrinal language as veiled imperial commentary. That bishops like Hilary and Lucifer had political implications in their theology is undeniable; whether they intended to theorize imperial sovereignty is another matter.

Yet these are not so much criticisms as reflections on the book’s ambition. Christ the Emperor seeks to reframe an entire field, and in large if not all parts it succeeds. It restores political theology to its proper place in Roman intellectual history and forces readers to reckon with the ways in which power, whether imperial, divine or ecclesiastical, was imagined, debated, and sanctified in the fourth century. Smolin’s argument is not that theology replaced politics, but that it became its most important symbolic field. This insight has implications well beyond Late Antiquity. In an age when the entanglement of religion and political authority continues to provoke debate, Smolin’s study reminds us that many of our categories – sovereignty, legitimacy, and hierarchy – were first forged in the crucible of theological dispute.

This book will be of use to a wide range of readers. Historians of Late Antiquity will appreciate its fresh take on the Constantinian and the post-Constantinian world. Theologians will find much to reflect on in its readings of Nicene and anti-Nicene authors. Scholars of political theory may be intrigued by its implicit conversation with modern theories of legitimacy and sovereignty. And classicists will welcome its careful attention to the classical tradition within Christian rhetoric, especially in making use of Eusebius. It is particularly suited for graduate seminars or advanced undergraduate courses on late Roman political thought, early Church history, or the intersections of theology and empire. Its arguments are broad and provocative but grounded enough in the sources to provoke debate and discussion. In short, it is a model of interdisciplinary scholarship: conceptually bold, textually meticulous, and intellectually generous.

Perhaps the greatest strength of Christ the Emperor is its capacity to surprise. Few readers will come away without having learned something new, not merely about the figures it treats but about the nature of power itself. Smolin reminds us that power is not only exercised but imagined; not only enacted, but narrated; not only political, but theological. In so doing, he has written a book that deserves to be widely read, carefully studied, and deeply considered.

Table of Contents

Introduction (1–20) 
1. The Political Theology of the Emperor Constantine (21–141)
2. Eusebius of Caesarea and the Three Emperors (146–238)
3. Constantius II and the End of the Constantinian Settlement (243–382)
4. Athanasius of Alexandria, the Son of God, and the Sons of Constantine (387–417)
5. Lucifer of Cagliari and the Eternal Emperor (420–98)
6. Hilary of Poitiers and the Cosmic Unity of the Episcopate (501–561)
7. Athanasius and the Homoiusians against the Antichrist (565–608)
Epilogue: Jovian, the Valentiniani, and the Theodosian Settlement (611–38)
Appendix A: Timeline of Episcopal Councils (639–45)
Appendix B: Authenticity and Dating of Key Texts (646–63)

Discussion

1. Your refreshing treatment of Constantine’s relationship with Christianity avoids the usual triumphalist arc and instead highlights the complexity of his imperial persona. Might we go even further and suggest that Constantine used Christian theology primarily as a language of imperial innovation, or a means of expressing dominion rather than conviction? In other words, do you see Christ as the Emperor’s instrument, or the other way around? 

I am not quite sure that a dichotomy of dominion versus conviction is a tenable one in the fourth century. 

Your question, it seems to me, is ultimately inextricable from the one I’ve been asked most often about my project, particularly by nonspecialists: namely, “Do you think Constantine was sincere in his conversion to Christianity?” This is necessarily to some degree a psychological question—

and I deliberately avoided psychologizing as much as possible in my study. It is also just as much, I would argue, a theological or theoretical question. 

If one assumes on the one hand that there is a practice or discourse of politics that is purely “objective” and separable from all matters of belief or conviction, and on the other hand that there is a realm of personal or private conviction that is purely “subjective,” totally separable from matters of rule and governance, and accessible to a fourth-century Roman emperor, then one could certainly sketch the figure of a purely cynical Constantine who merely pretended to believe in Christianity, and who hence used Christ and Christianity as mere means to further his own objective-rulership purposes. But I do not honestly think that such a dichotomy would be even conceivable for anyone in the fourth century CE.

On a basic psychological level, Constantine was a person raised entirely in imperial milieus and rose to power through usurpation. As emperor, some of his most basic duties included marking his own power and status to his subjects more or less 24/7 and via nearly every action and word and gesture and garment, participating in extensive daily rituals focused on his power and status, and being the recipient of regular panegyrics discussing and defending that power and status. It would be difficult for even an ordinary, twenty-first-century person to live that sort of life for any period of time and not come to believe, with some genuine degree of conviction, in their own imperial persona; and this despite the fact that modern society is more or less designed around the conviction that all such concepts of cosmic power and status are cruel and absurd. It is unlikely, though, that a person in Constantine’s position, with his background, would experience any similar sense of disconnect or conflict. Then, too, Constantine had risen to power through drastic, risky actions that turned out extraordinarily successfully—another situation that frequently causes even modern persons to regard themselves as in some way uniquely chosen or favored by providence. To all this Constantine added a sophisticated and well-articulated philosophical and theological discourse that explicitly justified his status and rulership in cosmic and Christian terms; and it is, again, quite difficult to perform such a task without some degree of conviction, while the mere articulation of such a discourse might convince anyone of its truthfulness. 

On a basic level, then, I would agree that Constantine certainly did use Christian theology as a language of imperial innovation and a means of expressing and communicating and justifying his dominion over his subjects. We have no reason, however, to believe that this reflected a pervasive absence of personal conviction, or was in a basic psychological sense cynical or insincere on his part. 

Similarly, as I sought to articulate throughout my study, Constantine was well aware that when he adhered to Christianity he was putting himself into contact with not a mere abstract belief but a well-developed institution with its own leaders and its own sources of power and legitimacy; he ultimately became aware, if he was not at first, of the necessary negotiations and limitations this placed on his own power. In this sense, even in political terms, adherence to Christianity could not be merely for Constantine a way of articulating power; it also had to be a way of relating different forms and degrees of power and authority, and different sorts of people wielding power and authority, to one another and to himself. 

Similarly, dominion was certainly not all Constantine was seeking, or all that he articulated, by means of Christianity and Christian theology. Even taken in terms of rulership, Constantine’s goal as I have elucidated it was not merely to project but to legitimize his rule, by justifying it with respect to a broader vision of God, the cosmos, and morality. While I have argued that the distinctive aspects of Constantine’s theology all center on rulership, taken on its own terms his articulated viewpoint goes well beyond politics as such. There is no reason to believe Constantine was fundamentally indifferent to broader questions of morality, cosmology, and theology, and a great deal of evidence from his writings that he was indeed personally interested in these questions, and that he found at least some of the answers and discourses on these subjects provided by Christian theology convincing. 

Most fundamentally, though, the question ultimately depends on essentially theological and intra-Christian disputes: namely, does Christianity in fact privilege transcendent and/or personal forms of salvation over the kind of political dominion represented by the Roman emperor? The burden of the Constantinian and Eusebian forms of political theology outlined in my project is that the dominion and rule of the Roman Emperor Constantine is in fact of central salvific, cosmic, and eschatological importance for the Christian church, individual people, and the world. The burden of the contrary Nicene perspective, on the other hand, is that the dominion of any political ruler is always merely “secular” (i.e., contingent and temporary), focused primarily on merely this-worldly goods, and hence subordinated to the fixed, permanent sacraments, rituals, and structures of the clerical church necessary for gaining transcendent personal and communal salvation. 

I do think that the latter position, though not in so explicit a form, is far more deeply rooted in early Christianity than the former; and that Constantine would certainly have encountered it in some form during his engagement with Christianity. Nevertheless, Constantine certainly also

encountered clerics and forms of theology more amenable to his own pre-existing viewpoint on the cosmic and religious importance of his position, and, as I have argued, he ultimately chose to embrace these himself. This imperial theology, while ultimately the loser in episcopal and ecclesiastical terms, certainly possessed the resources to argue for its position in Christian terms, and even after the victory of a basic Nicene orthodoxy, articulations of the Emperor’s cosmic and salvific importance continued to find expression in other and more limited and contested terms over the following centuries within the Byzantine Empire. 

2. You rightly place significant weight on the performative aspects of imperial piety, processions, inscriptions, and architectural gestures. To what extent do you think the Christianisation of imperial space was understood by contemporaries as sincere religious expression and to what extent as the emperor’s latest stagecraft? That is, did Romans believe they were truly praying to an otherwise-heretofore-shunned god, or just clapping at the show to support a form of the latest imperial fad?

Imperial ritual was effective, I would suggest, precisely because it was not only seen as a form of cynical performance only cynically submitted to by subjects. Imperial rituals and forms of communication were normatively accompanied by actions intended to not just perform but demonstrate imperial status and beneficence through acts of judgment, architectural building, giving away of gifts, money, privileges, etc. Similarly, I would argue that even the rituals themselves were effective only to the degree that they expressed and relied upon values already widely shared and exemplified in Roman society at every level. The Roman Empire was itself a highly communal, performative, and hierarchical society built to a significant degree around asymmetrical relationships of superiority, beneficence, and dominance. When Roman Emperors enacted these values as the apex of the social and political hierarchy, they reinforced the society around them and the pre-existing assumptions and convictions of many of their audience.

That being said, the impact, or indeed the degree, of the Christianization of imperial ritual is a very important question. It is also, however, a difficult one to answer given our lack of detailed information on imperial rituals in this period. Eusebius of Caesarea describes a number of ritual Christianizations purportedly introduced by Constantine, including the incorporation of Christian symbols and terminology, the integration of Christian clerics (including, at times, himself) into imperial ritual as ritual actors and panegyrists, the incorporation of Christian festivals into the imperial festal calendar, and perhaps most importantly (for Constantine himself) the delivering of sermon-like theological discourses by the emperor himself.

The impact of these Christianizations on public consciousness is difficult to estimate, but likely was meaningful. For both Christian and non-Christians, I would suggest, it signified at a minimum that the Christian God was the emperor’s patron deity, and indeed the patron deity of his dynasty: and being the patron deity of a successful emperor and dynasty was likewise at minimum indicative of a powerful deity whom it would be wise to propitiate. Acceptance of either concept, however, did not necessarily mean exclusive adherence to the actual institution or

practices of Christianity; indeed, it did not precisely indicate this even for Constantine himself as a non-baptized catechumen.

Likewise, I broadly agree with the argument of Hal Drake that much of Constantine’s ritual idiom was capable of being accepted by pagans in terms of a “consensus monotheism” by which the Christian God could be viewed as a form of the ultimate monotheistic God believed in by most pagans by the fourth century, with distinctively Christian symbology and theology either ignored or reinterpreted as merely one expression of more universal philosophical truths.

Still, in his public words and acts Constantine did consistently and clearly utilize specifically and distinctively Christian terms, symbols, and concepts, polemicize against pagan sacrifice, and publicly and legally privilege and support the actual institution of the Christian church. Many people in the fourth century would have regarded that as good enough reason in itself to see the success of the dynasty of Constantine and the Roman Empire as bound up with Christianity. For some, this would have been incentive enough to intellectually explore or even ritually adhere to Christianity themselves.

Overall, however, my own conclusion is that the degree of substantive Christianization of imperial ritual in the fourth century was quite minimal. There were few if any substantive ways in which the emperor’s rituals changed in terms of either the basic values they embodied or their basic portrayal of the emperor as a privileged cosmic and semi-divine figure sitting at the apex of the social hierarchy and relating to his subjects through asymmetric relationships of dominance, command, and beneficence. It would certainly have been possible to participate in Roman imperial relationships and ritual without in any way consciously adhering to or even taking substantive notice of Christian elements, and certainly without seeing oneself as personally worshipping the Christian God. I would think it highly likely, therefore, that there were some who did regard the Christian aspects of imperial ritual as more or less surface-level or temporary. 

By contrast, in the Byzantine Empire over the next two centuries, a much more Christianized and indeed clericalized imperial ritual would be developed that did, indeed, rely to a large extent on a clear set of shared Christian values between emperor and people. We see little trace of that in the fourth century, even in the reigns of emperors like Constantius II, who regularly attended church councils, or like Theodosius, who supported Nicene theology.

That being said, as I indicate in the epilogue of my book, the primary impact on the general public would not come from the degree of Christianization of imperial ritual as in the increasing participation of that general public themselves in the clerical, sacramental world of Christian ritual. Very few Romans would have had the privilege to participate in rituals involving the Emperor personally—though, of course, far more would have participated in imperial cult festivals, in the veneration of statues and coinage of the Emperor, and in local civic and familial rituals. The principal rituals of Christianity did, however, embody substantively different values from those found in Roman religious or civic rituals tout court; and over the course of the fourth century, it is clear that they took on ever more regular and more central importance in the lives of the Roman citizenry up to and including the Roman emperor.

Hence, as I suggested in the epilogue, much of the conflict between Christianity and the Roman emperor in the fourth century can be understood in the light of the gradual eclipsing of Roman imperial and civic rituals by Christian sacramental and liturgical rituals and the increasing incorporation of the Roman Emperor into this new Christian ritual cosmos in a subordinate position. In this sense, Theodosius’s limited incorporation of Christian elements into existing imperial rituals was of far less import than his weekly attendance at Christian services, participation in Christian sacraments, and public acceptance of Christian penitential practices. Given that every act of the emperor was supposed to serve as a performance and communication of his power and status to his subjects, the emperor’s very public and habitual acceptance of a common, subordinate “lay” role in Christian rituals, sacraments, and public gatherings in itself constituted new imperial rituals communicating a radically new concept of the emperor’s role in relationship to the divine and his subjects alike. This, at least, could not be reasonably treated as a mere fad, even if it was seen as a shame and a scandal. 

A full discussion of this question, however, would take us into the development of a more liturgical language of imperial uniqueness, power, and status within the Christian ritual cosmos under the Byzantine Empire. But that would take another study of its own.