[1] Its full name was Saint John the Forerunner by-the-Dome (Greek: Ἃγιος Ἰωάννης ὁ Πρόδρομος ἐν τῷ Τρούλλῳ, Hagios Ioannis ho Prodromos en tō Trullō).

The building lies in Istanbul, in the district of Fatih, in the neighborhood of Çarşamba, one of the most (Islamic) conservative areas of the walled city.

It is located in Koltutçu Sokak, along a small square, surrounded by new buildings, less than 400 metres (1,300 feet) to the south of the complex of the Pammakaristos.

[3] At the end of the 16th century, during the reign of Sultan Murat III, Hırami Ahmet Pasha, formerly Agha of the Jannissaries, converted the church of the Pammakaristos into a mosque.

Before restoration, the building was in a very bad condition: the narthex was almost completely ruined, the columns had disappeared, and the paintings were barely visible.