Turkey’s Decision to Turn Hagia Sophia Into a Mosque Dismays Christians, Neighbors, Historians

ISTANBUL—With its huge dome and towering minarets, Hagia Sophia is to humanity what the Grand Canyon is to geology: an open-air book that concentrates nearly one and a 50 % millennia of historical past as the successive heart of Orthodox Christian and Muslim empires, punctuated by ransacking, fires and earthquakes.

But by selecting on Friday to renovate back into a comprehensive-fledged mosque a setting up that has been a museum because the 1930s and has come to be a impressive symbol of ecumenical relations, Turkish President Recep Tayyip Erdogan sent…