The oldest church building in Tarsus District is the “Old Mosque”, which has been used as a mosque since the 15th century. Then-church Old Mosque was actually built under the orders of the Armenian King Oshin at the beginning of the 14th century, and it was known as the St. Paul Church. Armenian inscriptions can still be read on basalt epitaphs placed on the doors of the rooms located on either side of the apse. This structure was renovated and transformed into a mosque in 1415, during the rule of Ramazanoglu Ahmet Bey. This is the oldest structure from antiquity still in use here.