The Bayezid II Mosque (in Turkish: Beyazit II Camii) is one of the mosques of the Ottoman sultans, and it is one of the largest mosques in Istanbul, Turkey. This great mosque, which was built by Sultan Bayezid II, was built between 1501 and 1506 AD, and the design is attributed to the engineer Khair al-Din (who died in 1512 AD). The dome of the mosque was partially rebuilt after the earthquake of 1509 AD, and repairs were carried out under the supervision of Mimar Sinan in 1574 AD. The mosque is located on the third hill of the city of Istanbul, on the site of Theodosius Square in the old Istanbul district. The engineering architecture is characterized by pointed arches and magnificent domes. There is an eight-shaped fountain in the mosque for ablution. The mosque is currently being renovated and extended until 2017.