The disintegration of the Seljuk Turks led to the rise of the Ottoman Turks. Their first important leader was Osman I Bey, who attracted Ghazi warriors and carved out a domain in north-western Asia Minor. Attempts by the Byzantine Emperors to drive back the Ottomans were unsuccessful, and ceased in 1329 with the Battle of Pelekanon. Following a number of civil disputes in the Byzantine Empire, the Ottomans subjugated the Byzantines as vassals in the late 14th century and attempts to relieve this vassal status culminated in the Fall of Constantinople in 1453.