I’ve posted every so often about the relationship between informal power and ecclesiastical hierarchy: [link] [link] [link]. As a quick summary, informal power is the sort of power that accumulates in kafkaesque bureaucracies where many people have influence and veto-power over a final decision, but no one has responsibility. It’s dangerous because there’s a great deal of uncertainty over outcomes, and uncertainty leads to conflict (and violence, and insecurity, and arms-races). Religions almost invariably exercise capacities (like teaching their adherents how to distinguish between holy and unholy, sin and righteousness, salvation and damnation) that are not themselves laws or judicial rulings, but nevertheless mold how ordinary citizens make sense of laws and judicial rulings. Therefore organized religion must be supervised by the same sovereign who makes formal law, or else it will become yet another bastion of informal power and social subversion. Disorganized religion is typically not a threat, but it can become a bastion of informal power if tiny independent congregations are all nudged in the same directions by a few powerful coordinating forces.
But the conditions for political harmony are not necessarily the conditions for theological unity.
It’s remarkable that the main schisms in Christianity started immediately after the conversion of Constantine, and continued to accumulate at an alarming rate under the Eastern Emperors until the latter had been forced back practically into the theme of Byzantium itself. No matter how many branches were already in schism, so long as there were chariot races to watch in Constantinople you can bet your last bezant that there was some new religious factionalism brewing in the Greek Church.
But then once the infidel had triumphed in the East, and the Greek Orthodox metropoleis were reduced to the status of tolerated millets within the caliphate, they managed to remain unified for the next 500 years.
The only remaining autocephalous Eastern Church which was sufficiently free of Muslim suzerainty to recreate caesaropapism was the Russian Orthodox Church. But barely had the Romanovs cobbled together an empire worthy of the name before the Patriarch Nikon had blown it apart again.
Likewise, after the Western Church went into schism with the patriarchs loyal to Byzantium, Western Europe was free from schism for hundreds of years (despite many sharp disagreements about theology and politics)… right up until the point that the Holy Roman Emperor was once again the most powerful prince in Western Christendom. And then bam, immediate schism.
These three examples don’t align perfectly. The pattern may be spurious. In Russia, to a first approximation, the issue seems to have been that as the expanding Russian Empire drew more and more fragments of the Slavonic/Greek Church within itself, liturgical peculiarities became a rallying point for rebels in the newly-incorporated provinces. So the Romanovs had an interest in religious uniformity, which meant they were shopping around for rationales to force one side to conform to the other. Ultimately the excuse they liked was that the Old Slavonic liturgical texts didn’t match the standard Greek texts… so they must be corrupted… so the Muscovites should adapt their liturgy to that of their emperor’s newest subjects. Insta-schism.
(In the end the rationale turned out to be spurious; it was the Byzantines who had made alterations to the original forms, not the Slavs. Whatever.)
I’m not qualified to comment on the Russian schism in depth. But superficially, at least, the case sounds very similar to the difficulties the Stuarts had with their newly-united kingdoms. It would have been easy enough to impose religious uniformity on England or on Scotland (assuming the reigning monarch wanted a uniformity of belief in the ballpark of the variation that already existed). But the task of imposing one standard on both was more difficult, because it meant one of the kingdoms would get a rather radical new policy. And the task of imposing two independent standards was hardly more promising, because it meant the British Presbyterians would have a permanent stronghold in Scotland from which to plot the takeover of England, and the British Episcopalians would have an analogous base of influence in England. (We haven’t even mentioned Ireland yet, so imagine trying to square all of this…)
The schisms in the Eastern Empire look more like purity spirals, but I don’t want to say too much off the cuff. Interpreting Byzantine history is terribly difficult. Roughly speaking, symbolic conflicts can easily take on an “everything not permitted is forbidden”-aspect if offense is a more powerful strategy than defense. “Proving” that some theological position X is totally permissible and non-heretical is quite difficult (especially if that means proving that it is absolutely consistent with every article of faith which might be essential to orthodoxy). Showing that the opposite doctrine, not-X, could be taken to contradict some interpretation of some orthodox doctrine is, by comparison, much easier. But this means that every school accused of error will want to quickly build a case that all of their opponents are heretics, as a form of self-defense.
Charles V had problems that match “multi-kingdom balancing act” and problems that match “symbolic arms race”. The best thing the Hapsburgs could have done for the stability of their empire — from a purely instrumental point of view — would have been to blow up the Brenner Pass to make sure that no German monks ever got within 100 miles of the Roman Curia. Taking off my Christian-hat and putting on my empire-hat, I will restrict myself to the observation that the mores of Renaissance Italy differed significantly from those of Germany, and standards of pious behavior differed too. If it was impossible for the Emperor to prevent his subjects from being aware of their differences, the next best thing would have been to try to convince the residents of each duchy that their responsibility for the religious orthodoxy of their neighbors ended at the borders of their feudal lord’s domain.