Turkey’s President Tayyip Erdogan joined thousands of worshippers at Hagia Sophia today for the first prayers there since he declared the monument, revered by Christians and Muslims for almost 1,500 years, a mosque once again.

Erdogan and his top ministers, wearing white facemasks as a precaution against Covid-19, knelt on blue carpets at the start of a ceremony which marks the return of Muslim worship to the ancient structure...