Mehmed II, officially Sultan Mehmed the Conqueror, Caliph of Islam, Caesar of Rome (30 March 1432 – 1 July 1491) (Ottoman Turkish: محمد ثانى), was Sultan of the Ottoman Empire from 1444 to September 1446, and later from February 1451 until his death. At the age of 21, he conquered Constantinople and brought an end to the Byzantine Empire, transforming the Ottoman state into an empire.