*Editor’s note: Before relations cooled between Turkey and Israel, untold thousands of Israelis visited Turkey for vacations and business. Many of us walked through the enormous, magnificent historical Hagia Sophia Church that has functioned for decades as a museum of Turkey’s Christian roots. Edy Cohen explains why Turkey’s current conversion of the huge, ancient “megachurch” building into a mosque, is a pragmatic move calculated for its effect within the Muslim world.

Turkish President Recep Tayyip Erdoğan announced a surprise move without coordination or prior notice. The Hagia Sophia Church (“Holy Wisdom” in Latin) was built in the 4th century as a Byzantine church, but was converted on Friday into a mosque (a Muslim house of prayer), following a decision by the Turkish court and the final confirmation of the Turkish president.

Many saw Erdogan’s decision as a move aimed against Christianity and the free world, but in my opinion this decision was aimed first and foremost to please the Arab Muslim peoples. If a...