Like the Mamluks, the Ottomans operated their own system of slave recruitment, primarily in their Balkan provinces. Young Christian boys were taken from their villages in an annual conscription known in Turkish as the devshirme, or “boy levy.” They were sent to Istanbul, where they were converted to Islam and trained to serve the empire. Athletic boys were sent for military training, to fill the ranks of the crack Janissary infantry regiments. Those with intellectual promise were sent to the palace to be trained for civil service in either the palace itself or the bureaucracy.
By modern standards, the boy levy appears nothing short of barbaric: children sent into slavery to be raised far from their families and forcibly converted to Islam. At the time, however, it was the only means for upward mobility in a fairly restrictive society. Through the boy levy, a peasant’s son could rise to become a general or grand vizier. Indeed, entry to the elite ranks of the Ottoman military and government was more or less restricted to devshirme recruits. The fact that the Arabs, who in their great majority were free-born Muslims, were excluded from this practice meant that they were greatly underrepresented among the power elite of the early Ottoman Empire.
Rogan, Eugene, “The Arabs”