Osman I was the founder of the Ottoman Empire. He was born in 1258 and got the title bey (chief) from his father, Ertoğrül, as ruler of the Söğüt tribe in 1299. (Osman's son Orhan renamed the tribe Osmanli after his father). The birth of the empire originated with the conquest of the Turkish tribe of Eskenderum and the city of Eskişehir in 1301-03. With the fall of the Byzantine fort at Yenişehir (transl.: New Town) the turks where ready to launch a siege at the large Byzantine towns of Bursa and Nicaea (now İznik). Osman I died in 1326, the year before the two cities fell. He was after his death given the title of ghazi (holy islamic warrior) by his successors.

Preceded by:
Ertoğrül
? to 1299
Osman I
1299 to 1326
Succeeded by:
Orhan I
1326 to 1359