In his Erasmus lecture (featured in the current issue of First Things), “Christianity Face to Face with Islam,” Robert Louis Wilken makes a generalization that seems unassailably true:

Most of the territories that were Christian in the year 700 are now Muslim. Nothing similar has happened to Islam. Christianity seems like a rain shower that soaks the earth and then moves on, whereas Islam appears like a great lake that constantly overflows its banks to inundate new territory. When Islam arrives it comes to stay—unless displaced by force . . .

But Kosovo, where approximately 85 percent of the population is nominally Muslim, may prove to be a striking exception.