The first military unit of the Ottoman State was an army that was organized by Osman I from the tribesmen inhabiting
western Anatolia in the late 13th century. The main corps of the Ottoman Army included:
Janissary: Infantry units recruited at a very young age from the non-Muslim ethnic groups of the empire and raised as Muslim Turkish warriors; also forming the Sultan''s household troops and bodyguard.
Sipahi: Elite cavalry knights who were granted tımars (fiefs) throughout the empire''s lands. Their alternative name was Tîmârlı Sipahi (Enfiefed Knight).
Akıncı: Frontline cavalry units of the Ottoman Army which raided and scouted the border areas and outposts.
Mehterân: Ottoman Army Band which played martial tunes during military campaigns. The mehterân was usually associated with the Janissary corps.
The Ottoman army was once among the most advanced fighting forces in the world, being one of the first to employ muskets. The Ottoman cavalry used bows and short swords and often applied nomad tactics similar to those of the Mongol Empire; such as pretending to retreat while surrounding the enemy forces inside a crescent-shaped formation and then making the real attack.