Territorial evolution of the Ottoman Empire
Suleiman I ( "Süleymān", ; almost always "Kanuni Sultan Süleyman") (6 November 1494  – 5/6/7 September 1566), was the tenth and longest-reigning Sultan of the Ottoman Empire, from 1520 to his death in 1566. Suleiman became a prominent monarch of 16th century Europe. Suleiman personally led Ottoman armies to conquer the Christian strongholds of Belgrade, Rhodes, and most of Hungary. In 1541 he annexed central Hungary while Transylvania became an Ottoman vassal. However rest of the Kingdom of Hungary including western and northern (Upper) Hungary and Croatia still were Habsburgs possessions. Suleiman also conquered Iraq in his conflict with the Safavid dynasty. Under his rule, the Ottoman fleet dominated the seas from the Mediterranean to the Red Sea and the Persian Gulf.
Osman I
Osman I or Osman Gazi (; ; died 1323/4), sometimes transliterated archaically as Othman, was the leader of the Ottoman Turks and the founder of the Ottoman dynasty. He and the dynasty bearing his name later established and ruled the nascent Ottoman Empire (then known as the Ottoman Beylik or Emirate). The state, while only a small principality during Osman's lifetime, transformed into a world empire in the centuries after his death. It existed until shortly after the end of World War I. Historians commonly mark the end date at the abolition of the sultanate in 1922, the proclamation of the Republic of Turkey in 1923, or the abolition of the caliphate in 1924.