Mehmed II or Sultan Mehmed the Conqueror (30 March 1432 - 3 May 1481) was Sultan of the Ottoman Empire twice, first for a short time from 1444 to September 1446, and later from February 1451 to 1481. At the age of 21, he conquered Constantinople and brought an end to the Byzantine Empire, transforming the Ottoman state into an empire. Mehmed continued his conquests in Asia, with the Anatolian reunification, and in Europe, as far as Bosnia and Croatia. Mehmed II is regarded as a national hero in Turkey, and among other things, Istanbul's Fatih Sultan Mehmet Bridge, Fatih University and Fatih College are all named after him.