This mosque started life as the 11th-century Church of St Theodosia. Legend has it that one day before the Conquest, worshippers filled the church with rose petals in St Theodosia's honour and prayed for her intervention against the Ottomans. Their prayers went unanswered, but the invaders renamed the building Gül (Rose) Mosque after the petals they found on entering.

But legends, however appealing, are rarely true. In reality, the building was used as a shipyard warehouse after the Conquest and wasn't converted into a mosque until the reign of Beyazıt II (r 1481–1512). The extremely high central dome is an Ottoman addition and the pretty minaret dates from the rule of Selim I (r 1512–20).