Twenty years ago, in July 1995, Serbian forces killed some 8,000 Muslims in and around the Bosnian town of Srebren­ica. That was by no means the only such instance of interreligious violence and ethnic cleansing in modern times, especially along the tectonic fault lines that divide Chris­tians and Muslims. One can note, for example, the Armenian Geno­cide during the First World War and the carnage wrought by modern-day Islamists in Iraq and elsewhere.

But there is another, critical side of the story, one scarcely known in the West. Repeatedly along those religious frontiers Christian forces perpetrated massacres of Muslims and even acts of genocide. Those largely forgotten crimes shaped the religious geography.

With some allowance for minorities, most Westerners think of Europe as historically Christian and the Middle East as overwhelmingly Mus­lim. Such a division would have astonished observers as late as 1900. From the 16th century through the 20th, even when Ottoman Turkey ruled the Middle East and the Balkans, much of that region was very diverse in faith as well as ethnicity. Instead of today’s fairly homogeneous Middle East, we would do better to think of a religiously complex region extending from the Danube to the Eu­phrates, from Belgrade to Bagh­dad. Our modern religious map is a product of decades of violence and ethnic cleansing during which Christians were driven out of the Middle East and Muslims from Europe.