For nineteenth-century historians, the question of how Christianity went from being an obscure cult to becoming the official religion across Europe was answerable simply by pointing to what they saw as its innate superiority, whether in organization, doctrine, or both. Swiss historian Jacob Burckhardt, for example, argued that Constantine had chosen Christianity because he saw in it, unlike in other cults, the potential to create a Church that could help him run his empire.

While individual historians might differ in identifying the features that made Christianity superior, the underlying assumption was similar. Indeed, even Frederick Engels deployed a version of this argument when he described how Christianity won “what can be called a Darwinistic struggle for ideological existence,” as its ability to appeal to the masses of the oppressed enabled it to “develop its character of world religion by natural selection in the struggle of sects against one another and against the pagan world.”

The idea that Christianity was simply destined to become dominant is now somewhat dented by the fact that, as historian Peter Heather puts it, modern Europeans “have chosen in large numbers not to adhere to Christianity in practice, whatever they might enter on census returns.” It was in any case never really an idea that offered a materialist explanation for the Church’s centuries-long survival.

In order to account for that survival, we need an understanding of the role that the Church has played in ruling-class power across vast periods of time, from the ancient state to feudalism and then through the transition to capitalism. First of all, it is important to note that what Anderson calls the “essential continuity” of the Church throughout its history can be overstated.

The Church that became part of the imperial administration in the late Roman Empire was fundamentally different from the medieval Church, which itself was of course significantly transformed by the post-Reformation period. Part of the story of the survival of Christianity in general and of the institutional Church in particular is the story of its adaptability.

The Church had to coexist for many centuries after Constantine with the survival of pagan practices, even in the most unlikely places. Canons passed at a Byzantine council in 691–92, for example, show that people in the Byzantine Empire, formally Christian by that point for nearly four hundred years, were still singing songs at the wine harvest in honor of the pagan god Dionysus.

We mostly know about these practices from law codes banning them. Yet Christianity in the early medieval period still made extensive adoptions of preexisting pagan festivals into the Christian calendar and Christianized other pagan practices, such as wearing amulets to ward off disease. Doctrine also shifted to serve the needs of new believers. When early medieval Christianity had to win over aristocratic warrior elites, for example, it promoted the more warlike Bible verses and introduced practices like liturgies giving thanks for victory in battle.

Over the course of the early medieval period, the Church felt able to become less tolerant of surviving pagan practices. However, it retained its necessary adaptability. Successive challenges posed by popular understandings of religion and what the role of the Church should be, from the eleventh-century reform movement to the Reformation, pushed the Church into continual renewal. While this was by no means always an easy process, the dialectical process of constant change prevented the Church from becoming fossilized and arguably helped it to survive.

Any assessment of the reason for the success of the Christian Church in surviving past the end of the Roman Empire and spreading across the post-Roman west has to consider the class or classes to which the Church was managing to appeal. It is clear that the spread of Christianity was driven by elites.

This is not to say that there were no sincere Christians among the peasantry or the urban poor — there clearly were. The key point is that the history of the conversion of the Roman Empire and then of post-Roman kingdoms to Christianity is the history of elite decisions to adopt the religion and encourage or mandate widespread conversion. This was not a process that happened organically; nor was it primarily driven by popular enthusiasm.

From a very early stage in the history of Christianity, it was attracting upper-class adherents. Historians no longer share the view of Christianity that Engels put forward, presenting it as a religion of “the labouring and the burdened” in the Roman Empire — at least not once we have gone past the first century.

It is true that into the third century, some writers were still accusing Christian churches of attempting to recruit “foolish and low individuals, and persons devoid of perception, and slaves, and women, and children,” but this was anti-Christian propaganda. By the second century, the ranks of Christian converts already included a few Roman senators and imperial administrators.

This success in winning upper-class adherents was not a flash in the pan. While Christianity was still a minority religion in the third century, its followers included major aristocrats like the family of Constantine. Constantine himself was not pushed into adopting Christianity by an upswell of popular belief, but rather chose to elevate what had become a credible elite religious affiliation. It may well have been his own religion from long before his official conversion story would have it.

Once Constantine had announced his Christianity, it became the religion for aspiring imperial functionaries to adopt if they wanted to get on. Christianity’s status as the imperial religion therefore drove the Christianization of the Roman imperial bureaucracy, so much so that by the time of the empire’s fall in the West, they were virtually synonymous. Why did Christianity not go the way of that lost imperial administration, and how did it manage to become sufficiently attractive to post-Roman elites to make them convert?

Historians often view the decisions by individual rulers to convert to Christianity in terms of the political considerations behind them. Conversion could make connections with greater powers: the adoption of Christianity by King Æthelberht of Kent in the early seventh century, for example, tied him into the Frankish world across the Channel.

It could also bind together alliances. The conversion of the Vandal army that conquered the Roman province of Africa in the mid-fifth century provided a unifying religion for a force comprised of, as Peter Heather observes, “Germanic-speaking Vandal farmers mingled with groups of Iranian-speaking Alan nomads, some Goths, some Romans, and many others besides.” Without this shared religion, the soldiers would have had neither culture nor language in common.

Seen in this way, we might consider the position that the Church adopted as the result of decisions like these as a purely superstructural matter. The Church had a clear ideological role in justifying the claims to supremacy of particular rulers and positioning them as ordained by God.

In the early medieval period, this is particularly the case for Carolingian rulers. Charlemagne and his successors, as Chris Wickham remarks, aimed at “nothing less than the creation of a collective moral framework for the salvation of the entire Frankish people,” with their continuing rule at the center.

With varying degrees of success, European monarchs continued to use the idea of the ruler as a figure who had been favored and appointed by God, and therefore set above other major aristocrats, throughout the medieval period. This notion carried over into the early modern period as the divine right of kings.

This view of the reasons for conversion sees the Church as part of the culture of medieval society, rather than as a body that played a role of its own in feudal relations of exploitation. In the words of Perry Anderson: “Its autonomous efficacy was not to be found in the realm of economic relations or social structures, where it has sometimes mistakenly been sought, but in the cultural sphere above them — in all its limitation and immensity.”

Such a perspective would still, of course, grant the Church considerable importance. The existence of the Church enabled the survival of classical learning and literacy from the Roman period into the Middle Ages, preserving some of the culture and administrative structures of the Roman Empire. In much of France, indeed, bishops were key to the very continuance of urban life after the end of Roman rule. Broadly speaking, towns that had bishops survived, whereas towns that didn’t were likely to disappear, even if they had formerly been significant Roman centers.

However, this interpretation would present the Church as being only tangentially related to feudal production — for example, in the sense that Church institutions were themselves feudal landowners, or because the secular administration made use of the literacy services that the Church provided. Ellen Meiksins Wood thus describes the Church as part of the “patterns of social order in Europe other than the characteristically ‘feudal’ relations between landlords, peasants and kings.”

For some, following the argument of Edward Gibbon, the Church was in fact a positive hindrance to the feudal economy, acting as a drain on society by removing so many people from productive activity to become monks and nuns. The Christian ideological support for royal authority came at a price, or so it would seem.

For others, historical circumstances enabled the Church to play a greater role in some places in the development of feudal exploitation, but not in others. Chris Wickham notes the role of the Church in the Carolingian project and sees it as a force assisting the development of exploitation in England. According to Wickham, however, this did not rise to the level of a central role in the feudal system as a whole, since in other places, such as Denmark, “the church was an add-on, even if an important one, to social and political developments that were occurring anyway.”

Yet it is possible to see the Church as constituting an essential part of the feudal system, rather than merely an adjunct to its operations. In some ways, this part remains an ideological one, as the Church not only provided the justification for royal power but also for labor. As Wood argues in relation to the Carolingian use of the Church: “Christian dogma and ritual were made to encompass all aspects of life with increasingly complex liturgical forms, placing an increasing emphasis on sin and on the correctional, disciplinary role of religion.”

But this ideological function does not represent the full extent of the Church’s utility under feudalism. It also played an intensely practical role, enabling feudal lords to control the work of the peasantry and to develop their ability to exploit them, whether those peasants were serfs or formally free.

Across Western Europe, from the tenth century on, ecclesiastical institutions led the way in systematizing the management of their lands by moving their peasants from scattered settlements into larger villages, where they could be more easily monitored and controlled. The Great Abbey of Cluny was already doing this on its extensive lands in the late tenth century. This served both as an example and a blessing for secular lords in the area to do the same.

The tithes system, through which everyone had to pay a tenth of their earnings to the Church, had helped to create this fixed structure in the first place by associating every settlement with a church to which tithes had to be paid. Building stone churches for these villages then anchored them in place, limiting the ability of even free peasants to move around. The parish system, developed by the end of the twelfth century, completed this process by bringing the countryside squarely under the control of the Church.

Not only did the Church establish where the peasants worked — it also increasingly managed working time, establishing the calendar of working days and feast days that would control the peasants’ working behavior. This was true to some extent even in the early medieval period.

Gregory of Tours, writing in the late sixth century, recounts various miracles that show the Church organizing labor for the benefit of secular lords. Such tales remind his audience that the power of the saints could strike down anyone who disobeyed the requirements of Church time. One story concerns a man who insisted on working his vineyard on the Feast of St Avitus: he was struck down immediately, “his neck twisted and his face . . . turned around to the back.”

Episodes like this show the perils of working when the Church told you not to. The same moral would equally well apply to those who did not work when they should. This control over working time had extended by the central Middle Ages to virtually every aspect of peasant life,  as James Brundage’s masterly flowchart of the sexual decision-making process according to the penitentials reveals.

Christine Caldwell Ames observes that the Church was asserting its authority during this period “through a variety of interlocked media that included inquisition, a new and inescapable authority over all souls and bodies.” The function of all this control was to increase the surplus labor extracted from the peasantry through intensive management both of the production process and of the reproduction of labor.

In this, feudalism was fundamentally different from an ancient state, which generally wouldn’t involve itself to such an extent in the question of how the surplus was produced, so long as the taxes were paid. The Church provided this intensive feudal exploitation with legitimacy.

According to its doctrines, lords, whether ecclesiastical or secular, were not simply extracting the products of peasant labor by force (although of course the threat of force was always there). They were collecting what God had mandated the peasants to hand over. While any lord could seize the sheep of peasants like a bandit, it was only lords in a Christian kingdom who could benefit from a peasantry neatly arranged and managed to maximize their exploitation.

Of course, there were significant regional and temporal variations in the intensity of feudalization across medieval Europe. Areas where feudalism had not yet been taken to its fullest extent, such as parts of Southern France before the Albigensian Crusade of the early thirteenth century, are in many ways the exceptions that prove the rule.

The world of twelfth-century Languedoc, where villages could relocate or fortify themselves at will and where many secular lords did behave rather like bandits, emphasizes by way of contrast the intensive feudalization of areas like England and Northern France. The Church did not simply survive the transition from late antiquity to feudalism; it was part of the creation of the feudal system.

This account of the Church’s essential role in feudalism could give the impression that Christianity in the medieval period was only about exploitation — a one-way system of belief that was simply imposed on the peasantry to their detriment. Yet there was another side to the use of Christianity for social control. As a result of the Church’s position in establishing and maintaining feudal control, religious dissent — heresy — of all but the most academic kind always had the inherent potential for social protest.

Some heretical movements look like obvious social revolts. This is true in the early Church, with examples like the Circumcellions, a fourth-century group in North Africa who were denounced as heretics. The Circumcellions were mostly seasonal agricultural workers and fought against slavery and exploitation, ambushing rich travelers and making them run behind their own vehicles “like slaves.”

During the central medieval period, we have examples like the heretic Éon de l’Étoile and his followers, who were active in Brittany in the 1140s and who raided monasteries and churches and feasted on their booty in the forests. Éon believed that he was instructed by God and that the words of the liturgy were directed at him personally, but hatred of the wealth and exploitative power of the Church is also implicit in his actions and those of his followers.

In similar fashion, the followers of Fra Dolcino in Piedmont in the early fourteenth century attacked towns and even ransomed a local military leader. However, they clearly stated that they were inspired by religious beliefs — in the necessity for apostolic poverty against the corruption of the Church, and increasingly in the proximity of the apocalypse and their special role in it. They maintained that they were “subject to God alone and to no man, just as the apostles were subject to Christ and no one else.”

Their beliefs were a clear challenge to ecclesiastical and by extension secular authority. Under Fra Dolcino, they were explicitly rejecting mainstream society and attempting to build a society of their own, with all the confrontation with the existing powers that such a course of action implied.

Urban revolts could also combine calls for religious reform with expressions of secular social protest. Arnold of Brescia, for example, led a popular insurrection in 1155 in Rome against clerical corruption that blended “religious idealism and political radicalism,” as Michel Mollat and Philippe Wolff observe.

In 1196, London saw a major revolt led by William Longbeard. Like Arnold of Brescia, Longbeard was a holy man (signified by the long beard) but was acting here in an unauthorized role rather than as a representative of ecclesiastical authority. His was an apocalyptic message but also a revolutionary one, not merely asserting the rights of the poor but associating them with the saved and the powerful with the damned.

The potential for religious expression to serve as a channel for social protest was significant even when the movements concerned did not end up in open revolt. At one level, individuals leaving their lives and possessions for a nomadic, ascetic life would be simply following the example of the apostles of the Gospels. Yet popular enthusiasm for apostolic poverty and those who practiced it could be a challenge to the Church and secular authorities throughout the medieval period. Even where the Church itself made use of such popular religious enthusiasm, as in the Peace of God movement in the late tenth and early eleventh century, there was always the potential for movements for religious reform to become vehicles for popular protest.

These religious rebels were not cloaking their secular aims in religious language, nor were they suffering from false consciousness by assuming the religious framework of their exploitation. Just as Christianity had become an intrinsic part of feudal exploitation, so ideas of religious reform were a genuine part of resistance to that exploitation throughout the medieval period.

The challenge that this posed to the Church was real, but the adaptability that it required was also essential. The dialectic of challenge and response that religion as social protest set up is part of the story of the Church’s survival.

Given its wealth and position as part of the establishment, the Church was probably always likely to survive the transition from feudalism to capitalism in some form. However, it is worth noting that early modern rulers maintained and extended the medieval interest in ideological control, in Protestant states (where the secular state seized authority over the Church) as well as Catholic ones.

The intense management of citizens’ souls as a means of controlling production continued, whether managed through the Inquisition or other forms of law enforcement, both secular and ecclesiastical. This shows the continuing relevance of Christianity to exploitation, even at a time when many states were rejecting the authority of the Catholic Church and the Pope.

The part played by Christian conversion efforts in the history of European colonialism demonstrates how even into the modern period, Europe’s ruling classes saw Christianity as a force with a useful disciplining effect on labor. Attempts to enforce church attendance on working-class people where possible also testify to such attitudes. In England, for example, church attendance was theoretically compulsory into the nineteenth century, with more stringent and enforced requirements on working-class people within reach, such as residents in poorhouses or almshouses.

The modern history of the Catholic Church in particular has shown it struggling to adapt to liberalism. However, the centrality of the Church to systems of exploitation since the fourth century has meant that it still constitutes an institutional part of Catholic states, both in Europe and (thanks to colonialism) around the world.

The fact that this remains the case today is not so much a commentary on the nature of religion per se, or indeed the specific features of Christianity, as it is a reminder of how much capitalism inherited from feudalism. The Church was an intrinsic part of feudalism, and that is why it is still with us today.