Turkey’s president is playing religious politics

IT WAS BORN as a church, one of the icons of the Byzantine world, before being converted into a mosque by the Ottoman Turks and into a museum by their secular-minded successors. But now it would be transformed again. Workers squeezed a bland wooden minbar into a corner of the nave and a mihrab into a nearby portico, drew panels and screens to obscure the dazzling 13th-century Christian frescoes looking down from the vaults and the dome, and unfurled a red carpet over the marble floor. A muezzin summoned the faithful to prayers. The Hagia Sophia was now a mosque.

That was in 2013, and not in Istanbul, home of the Hagia Sophia known to millions of tourists worldwide, but in Trabzon, another Turkish city once populated by Greeks (and known in English as Trebizond), home to the ancient shrine’s much smaller and younger namesake. There are at least five former Byzantine churches dedicated to the Hagia Sophia (“Holy Wisdom” in Greek) across Turkey. Over the past decade, four, including the one in Trabzon, have reopened as mosques. The same fate now seems to await the most important of them, the sixth-century Hagia Sophia, the grand old lady of Eastern Christendom, and Istanbul’s domed crown.

Formally, the decision rests with Turkey’s top administrative...