The Lost History of Christianity: The Thousand-Year Golden Age of the Church in the Middle East, Africa, and Asia—and How It Died

by Philip Jenkins

Islam also grew later on because Muslim regimes encouraged the immigration of fellow believers from other lands, who quickly outnumbered the older, native populations. Although religious change is commonly discussed in terms of conversion, it is often a matter of population transfer rather than of the transformation of personal convictions. As in the Americas following the Spanish and Portuguese conquest, converting an area to a new faith does not necessarily mean securing the allegiance of the whole people. Rather, the older inhabitants can be expelled, or are outnumbered and diluted by newer population stocks. In the Middle Eastern context, too, immigrants benefited from their different economic background. Anthropologists commonly find that pastoral peoples outbreed their sedentary peasant neighbors, and eventually end up owning most of their land. As the Middle East became progressively Arabized in language and culture, so the ground was prepared for the newly dominant religion. Gradually, after three or four centuries, Muslims came to constitute majorities, usually through peaceful means.