Those revenue holdings were formalized as
mukâṭaʿas, held by tribal leaders and ghazi commanders who used their revenues to feed, supply, and arm their followers. It was that type of
mukâṭaʿa that developed into the Ottoman form of fief, the
timar, which was the basis of Ottoman military and administrative organization as the European portions of the empire were conquered from the vassals in the 15th century and placed under direct Ottoman administration.