Islam has, throughout the history of its aggression against the West, benefited immensely by, and in many cases cunningly exploited the divisions within the West. Some of the first Byzantine provinces to fall after the Mohammedan Revolution were those, like Egypt and North Africa, whose internal repose had already been shattered by the conflagrations of the great heresies of Christian antiquity. Many Arian, Nestorian, and Donatist communities had been subject to oppressions and persecutions from the Empire in the decades immediately preceding the rise of Islam, and they welcomed the Muslim invader, even, in some cases, collaborated with him. ~Paul Cella, Enchiridion Militis
Paul Cella’s post makes on the one hand a very important, albeit somewhat indirect appeal for Christian unity against Islam and on the other points to the Islamic world’s capacity to absorb the resources of the regions it takes over and redirect them against its new foes. All of that makes a good deal of sense (though I am not quite so sanguine at the prospect of an Islamic Europe being in any meaningful sense preferrable to the current dispensation), and I applaud and recommend the post on those grounds.
However, the Byzantinist in me cannot really go along with the first paragraph of the post, because it is my firm opinion that the myth of collaboration, specifically monophysite collaboration, with the Islamic invader is unfounded in the evidence and anachronistic in its interpretation of the attitudes of the Roman Christians whose loyalty to their ecumenical polity is being traduced. Very simply, there is no evidence of monophysites collaborating with the Islamic invader. In fairness to Paul, this is something that Byzantinists have only been coming around to in the last 20 years or so and it has not penetrated very far beyond the scholars themselves. In fact, I am taking a view that is a bit contrarian, so you will be able to find a number of learned authors who would challenge the interpretation I’m giving here, but I want to assure everyone that this seems the most reliable interpretation of the evidence that we have so far.
There were cases of opportunistic individual collaboration during the invasions, as there always would have been, but every monophysite source we know condemns these collaborators and the invaders alike. There are examples in the seventh century of certain Armenian princes who sided with the Muslims as part of their resistance of the authority of the empire, and this was never entirely separate from resistance to church union imposed from Constantinople, but such collaboration as and when it did happen was determined by very specific political circumstances and was the exception and not the rule.
To the mind of the monophysite bishop and historian, John of Nikiu, who flourished at the end of the seventh century, the coming of Islam was a disaster brought on their empire by the Chalcedonians. Earlier, the Chalcedonian poet George of Pisidia had regarded the monophysites as Persian collaborators–not because there was evidence of any real collaboration during the invasion, but because they were supposedly objectively hostile to the Roman empire on account of their false doctrines. They had to be collaborators, because collaboration is the sort of thing heretics would do. But all other evidence points to the opposite conclusion. Moderns who may be looking for popular guerrilla uprisings of monophysites against the Islamic invaders or the like (which is apparently the only thing that would convince some people that the schism had little significance for the success of Islam) are expecting to see something that would never have happened in a late antique or early medieval society. Attributing capitulations of cities to religious dissent overlooks rather more straightforward answers, such as wanting to avoid having one’s city sacked and devastated, and seeks deep structural reasons for Byzantine military failure that are sometimes as easy to explain as the Byzantines’ losing particular engagements in the field for reasons that are mostly limited to the tactical situation in the battle itself.
The polemical constructions of seventh century imperial elites and the very modern assumptions of historians about what religious loyalties must have meant for pre-modern political loyalties (heretics must be traitors in an Orthodox empire when push comes to shove), based more in the history of the 16th and 17th centuries or perhaps even in the experiences of colonialism, have conspired to make the monophysites into the people who practically opened the gates to the Islamic invasions. However much it might flatter certain attitudes towards the monophysites, it was not the case and we should not base any analysis on history that is this badly flawed.
As for the Donatists, the evidence for North Africa is even spottier and less certain, and it is a rather big leap to associate the gradual disappearance of Christianity in North Africa in the high middle ages with the persecutions of the fifth and sixth centuries acting as a spur to political defection to the Islamic cause. Yet the argument is built up that North African Christians were disaffected because of the persecution of Donatism, which, on the reading of one prominent church historian, W.H.C. Frend, was also supposedly a social and political movement (a view I find extremely hard to believe) or, more crudely, perhaps simply a front for such a movement, and then again because of the condemnation of the Three Chapters and again because of monotheletism. But what is astonishing in all of this is that after all of these constant pressures and tensions with Constantinople North Africa remained firmly within the empire’s orbit until it was taken by force (Carthage fell in 698).
A very basic and understandable reason for this continued allegiance was the need for security against the non-Roman, nomadic population. This is not exactly a ringing endorsement for the empire, I suppose, but neither is there much reason to think that these religious quarrels (which had political implications of a different kind) portended the break-up of the state.
I do not say this out of any enthusiasm for the heresies and schisms themselves, with which I am perhaps less sympathetic than most, but out of an insistence that we must properly understand the history of our civilisation (the the history of the Eastern empire is assuredly part of our history in a directly meaningful way) if we are to succeed at shoring it up and restoring it in some measure.