File:Tarsus Eski Cami interior in 2005 4411.jpg

English: The church-based building in Çarşıbaşı was built in 1102, said to have been built as St. Paul's Cathedral. It is in Roman style, wide interior, with a narrow outer side, deep windows and thick columns. In some sources, a Hagia Sophia Church dating to the beginning of the Middle Ages is mentioned, and it is told that the Pope's envoy, Bishop of Mainz, Konrad Von Wittelsbach, recognized and crowned Leon I of Ruppen as the Armenian King on January 6, 1198.

The width of the hall, which is entered through the main gate in the west, is 19.30 meters and its length is 17.50 meters. There are half plaster columns and four free columns in two rows in two rows, at the level of these columns, separating the hall into three naves. There are also half columns on the north and south walls. In fact, these columns are gray granite and are likely to belong to ancient structures. The church was later converted into a mosque. It is known as the Old Mosque, Church Mosque or Baytemur Mosque. There are also different opinions on the date of construction. There are sources that date it to a wide range from the 2nd to the 14th century. In some sources, it is written that Seyfeddin Bay-Temur al-Harizmi converted one of the churches into a mosque in 1360 and therefore it was called "Bay-Temur Mosque". In some sources, it is recorded that Ramazanoğlu Şebabettin Ahmet Bey converted the church into a mosque and added a minaret next to it in 1415. It is known that when the Turks conquered a city, they turned the largest church there into a mosque, and the adhan was read and prayers were performed. It should be considered that both of the above rumors are true, and that it was restored and opened for worship in 1415, since it was the first mosque to be converted from a church.

Source: Mersin Provincial Directorate of Culture and Tourism archive / Mersin District Governorship