Chalcedon changed hands time and time again, as Persians, Bithynians, Romans, Byzantines, Arabs, Crusaders, and Turks passed through the area, which was badly damaged during the Fourth Crusade and came into Ottoman hands in 1353, a full century before Constantinople. Thus, Kadıköy has the oldest mosque in İstanbul, built almost a century before the conquest of Constantinople in 1453.