The Janissaries (Ottoman Turkish: يڭيچرى‎ yeniçeri, meaning "new soldier") were elite infantry units that formed the Ottoman Sultan's household troops and bodyguards. Sultan Murad I created the force in 1383. The number of Janissaries grew from 20,000 in 1575, to 49,000 (1591), dropped to a low of 17,000 (1648), then rebounded to 135,000 in 1826.

They began as an elite corps of slaves from kidnapped young Christian boys, and became famed for internal cohesion cemented by strict discipline and order. By 1620 they were hereditary and corrupt and an impediment to reform. The corps was abolished by Sultan Mahmud II in 1826 in the Auspicious Incident in which 6,000 or more were executed.

The Janissary corps were distinctive in a number of ways. They wore unique uniforms, were paid regular salaries (including bonuses) for their service, marched to music (the mehter), lived in barracks and were the first corps to make extensive use of firearms. A Janissary battalion was a close-knit community, effectively the soldier's family. By tradition, the Sultan himself, after authorizing the payments to the Janissaries, visited the barracks dressed as a Janissary trooper, and received his pay alongside the other men of the First Division. They also served as policemen, palace guards, and firefighters during peacetime. The Janissaries also enjoyed far better support on campaign than other armies of the time.

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