Muslims gathered for first Friday prayers at Hagia Sophia in Turkey’s Istanbul on July 24, after the premises’ conversion back to a mosque.br br Turkish President Tayyip Erdogan also joined the worshippers in the session.br br A top Turkish court announced this month that it annulled Hagia Sophia's status as a museum and Erdogan then turned it back into a mosque.br br It was a Christian Byzantine cathedral for 900 years before being seized by Ottoman conquerors and serving as a mosque until 1934.