Osman Gazi İngilizce Hayatı Osman I (1258-1324). The chronology of Osman’s career lacks certainty at every point, but the generally accepted tradition fixes his birth in 1258 at Söğüt (northwest of Eskişehir) where his father Ertoğrul was the leader of a band of frontier warriors. On the latter’s death, he became chieftain of the band and by the turn of the century he held the region including the cities of Bilecik, Inegöl, Yarhisar, and Yenişehir, the last of which became his center of operations against İznik and Bursa. The intent was to iso-late both these important Greek cities from assistance from Constantinople. In 1314 Bursa was placed under siege; it finally capitulated in 1326, the year of Osman’s death, and the city became the first capital of the infant empire. By this time Ottoman possessions extended as far east as Bolu, to Kandıra near the Black Sea in the north, and to İnegöl in the south; but the direction of political opportunity clearly lay to the west.