This is the Mustafa Çavuş Mosque, which is a Byzantine church turned into a mosque by Mustafa who was one of the sergeants of the Fatih Sultan Mehmed Han after the conquest of Istanbul. The church was built in the 13th century and has brick walls and a wooden roof. A wooden minaret has been built but was lost later. The entrance is on a terrain of the public transport company, and the mosque is still used by its workers.