Earlier this summer, during my copious time off, I spent some time with Norman Cantor and Thomas Noble. Norman Cantor is one of the great medievalists, author of Medieval History: The Life and Death of a Civilization. Thomas Noble used to teach at the University of Virginia, but I reached him through the Teaching Company, to whose products I am thoroughly addicted. They each had something interesting, and perhaps instructive, to say about Islam's 8th-century sweep through Asia Minor, Palestine, and North Africa.

It seems there was a major split in early Christianity concerning something called Arianism. It was one of those now-forgotten disputes about the nature of an incorporeal God ending up in a corporeal body. And it was supposely settled by the Council of Nicaea in the 300s. Except that large portions of Asia Minor and North Africa remained tied to the Arian doctrine, and found themselves increasingly disaffected with the Greek Church. In an age before disestablishment, this translated to disaffection with the Emperor in Constantinople, as well. Not an outright split, but a definite loss of loyalty. Noble and Cantor both speculate that when the Arab Muslim armies came through, the residents of these areas weren't inclined to fight too hard for an Emperor they felt had written them off. Remember that the Muslims demanded not conversion, but supremacy. Conversion was attractive because it allowed one to join the favored group. But it wasn't mandatory. Bernard Lewis opens his The Jews of Islam with an extended discussion of this point.

We may be facing a similar long-term problem vis-a-vis Europe. As Islam seeks to gain a foothold in Europe, we find ourselves at odds with European civilization over basic questions of liberty, equality, and how best to organize political life. An essentially secular Europe may not see any particular reason to resist Islam. And it certainly doesn't seem to feel it owes us any loyalty. (I am not writing off Eastern Europe. But I fear their being absorbed into an EU dominated by France and Germany.)

In order to avoid losing Europe altogether, we should focus on our essential similarities, which are large, while allowing ourselves to argue over what divides us, which is significant but not decisive.