For most of European history, the idea of the “nation state,” whose citizens professed only a single allegiance and national identity, did not exist. Most people identified with their local church or estate, giving the continent quite a bit of cultural diversity. As one writer put it, Europe was a “melting pot” of different peoples and nationalities. Its greatest cultural and religious differences existed as much within states as between them. Many of its cities — particularly the smaller ones at the intersection of old and new imperial boundaries — were truly multi-cultural societies, where Catholics, Orthodox, Muslims, Jews and others lived in “familiar juxtaposition,” according to the historian Tony Judt. This was tolerance only in a very narrow sense, of course, and it was occasionally marred by violence and hatred. “But it was real, and it survived into living memory.”
How might religion in Europa Universalis 4 change to represent this? There is already a mod called Dei Gratia which models the existence of religious minorities within a province through a very simple demographic system. The minorities are visible to the player as a modifier in the province window screen (although Paradox could probably create a more elaborate system). The introduction of religious demographics would allow new doctrines and ideas to spread in a much more organic way; conversions would no longer instantly flip a province, but instead shift the religious demography away from the old religion and toward new adherents.
However, religious conversion was not a decision to be taken lightly. The state’s religious authority essentially relied on the threat of violence. This set into motion forces that thrived on oppression and warfare, which even the state was sometimes powerless to restrain. Religious persecution could not necessarily spread civilization, but it could spread chaos, anarchy, lawlessness, and disorder. The result was not just unprecedented levels of violence and brutality, but also a complete collapse of law and the habits of daily life in the state. This “all-destructive fury” of religious violence, according to the historian Christopher Clark, became a compelling argument in favor of enlightened absolutism, embodied by the Leviathan state and the social contract. “Surely it was better to concede authority to the monarchical state in return for the security of persons and property than to see order and justice drowned in civil strife.” What this means for EU4 is that converting your subjects to the one true faith should have much more traumatic consequences: not only triggering an armed resistance, but also polarizing foreign opinion. With high enough unrest, your state would be looking into the abyss of full-scale religious war.
The violence and fury of religious warfare dislocated millions of ordinary citizens by destroying their lands and homes and disrupting their lives. This could be modeled by a simple population system which keeps track of expelled minorities as they flee from their oppressors and relocate to other countries. Foreign states leapt at the opportunity to offer asylum to oppressed minorities. According to Christopher Clark, this was a common way for rulers to demonstrate their religious zeal without risking armed conflict. Of the 200,000 odd Protestant Huguenots who fled the persecution of the French Wars of Religion, most were allowed to settle in Holland and England. A smaller minority of refugees, most of them from the poorer strata of society, fled further east to places like Brandenburg-Prussia, where they could expect state-subsidized assistance, cheap dwellings, and tax exemptions. As well as burnishing Brandenburg’s reputation as a defender of the Protestant faith, the refugees also provided the state with much needed skilled immigrants following the devastation of the Thirty Years War, which in game terms could be represented by increasing development levels.
Brandenburg was so successful at exploiting the “politics of religious rights” that the strategy became “a sort of fixture” of the Hohenzollern dynasty’s statecraft. This was especially true in the highly polarized atmosphere of the HRE. For example, in 1731, Frederick William I, King of Prussia, agreed to support Maria Theresa’s claim to the Austrian throne in return for allowing thousands of Protestant refugees from Salzburg to settle within Brandenburg’s borders. With a proper demographic system, it should be possible to make these kinds of deals in EU4.
In this era of unprecedented religious violence, states could only maintain domestic peace and stability by granting religious communities some autonomy and the right to worship as they saw fit, free from the interference of the ruler or the provincial elites (although the rights that were extended to one religious group didn’t necessarily apply to the others). Sometimes these religious rights were guaranteed by law. Sometimes they rested on the whims of the monarch. Either way, they provided a space for religious self-expression in an otherwise oppressive regime.
The problem, from the state’s point of view, is that their subjects did not necessarily share the same enlightened opinion about religious rights. The qualities of the enlightenment — tolerance, compromise, freedom of conscience, the capacity to absorb differences and passions, and a tacit agreement to avoid arousing all the old religious divisions of the reformation — were absent for most of EU4’s timeframe. Religious prejudice and strife were practically the norm, even if tolerance was enshrined in the government’s policies. If rulers attempted to impose the principle of tolerance on their subjects, they were almost certain to arouse resistance from the local nobles and elites who jealously guarded their own religious privileges and resented outsiders for tampering with their local traditions and customs. Tolerance would therefore mean taking sides, protecting minority communities against the chauvinism of the local elites and confronting hard-liners — a very difficult strategy that might not always keep religious violence at bay. That should make religion a more dynamic and interesting feature into the mid and late game.