The Gul Mosque (known in English as Rose Mosque) has one rather mysterious feature if one is to look carefully. In the second level you will see a small window with what appears to be a room inside. Inside this room in the upper floor is said to be a tomb, however it remains disputed over who this tomb belongs to. As a church in the Byzantine era, it was dedicated to St. Theodosia, hence it could be her relics kept there. However, another theory says that in that room above are the remains of the last Byzantine emperor Constantine XI Palaiologos who died in battle when the Ottomans captured Constantinople in 1453, however this may be highly unlikely as Constantine XI's body was never found, or so it's said... Whoever it is that is buried up there, this church was in ruins when the Ottomans captured Constantinople in 1453 and was only converted into a mosque in 1490, and being a mosque its past as a Christian church was hidden, hence it is not known who's tomb is in the upper floor, or if there is any tomb at all?