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.
Mehmed I
After winning the Interregnum, Mehmed crowned himself sultan in the Thracian city of Edirne that lay in the European part of the empire (the area dividing the Anatolian and European sides of the empire, Constantinople and the surrounding region, was still held by the Byzantine Empire), becoming Mehmed I. He consolidated his power, made Edirne the most important of the dual capitals, and conquered parts of Albania, the Jandarid emirate, and the Armenian Kingdom of Cilicia from the Mamelukes. Taking his many achievements into consideration, Mehmed is widely known as the "second founder" of the Ottoman Sultanate.