The village of Söğüt (formerly Thebasion until 1231) later grew into a town that served the Osmanli tribe as capital until the capture of the Byzantine city of Prusa in 1325 when the capital was moved to the far more luxurious palaces of the Byzantines.
Ko je po Osmanovi smrti prišel na oblast njegov sin Orhan, je očetu v čast pleme preimenoval v Osmanli.