The Omeriye Mosque is located near the main Municipal Market within the walled city of Lefkosia (Nicosia). The discovery of a number of tombs of Augustinian hermits indicates Omeriye Mosque was originally a church of the Order of the Augustinians dedicated to St Mary. The door of the main entrance belongs to the original 14th century building. This consists of a nave (41x11 metres) and was initially covered with cross vaults. The church would have initially been about 15 metres high, making it the most imposing building of medieval Lefkosia after Agia Sofia. The architecture of the building is generally simple, with heavy exterior facades and buttresses. The vaulted entrance preserves appreciable sculptural decoration. Remains of a later, Renaissance addition to the building can be seen on the northeast. The roof and superstructure, roughly to the height of the windows, was destroyed by Ottoman cannonades during the siege of Lefkosia (Nicosia) in 1570.
After the city fell, the Ottomans rebuilt the walls, added a wooden roof, plastered the interior and added a minaret. Mustapha Pasha converted the building into a mosque in 1571. The name of the mosque is associated with the 7th century prophet Omer who, legend has it, visited Lefkosia on his way to Egypt, and spent the night in the porch of the ruined church.