The Ottoman Army was the military force of the Ottoman Empire, which existed from the late 13th century until the early 20th century. It played a crucial role in the empire's expansion and defense, participating in numerous battles and campaigns across Europe, Asia, and Africa. The army was known for its diverse composition, including infantry, cavalry, and artillery units. The Janissaries were an elite infantry group within the Ottoman Army, originally formed from Christian boys taken through the Devshirme system. Over time, the army evolved, adopting modern military techniques and organization, especially during the 19th century, to keep pace with European powers.