Devşirme[a] (literally “collecting” in Turkish), also known as the blood tax, was chiefly the annual practice by which the Ottoman Empire sent military to abduct boys, sons of their Christian subjects (Rum millet) in the villages of the Balkans. They were then converted to Islam with the primary objective of selecting and training the ablest children for the military or civil service of the Empire, notably into the Janissaries.
Started by Murad I as a means to counteract the growing power of the Turkish nobility, the practice itself violated Islamic law. Yet by 1648, the practice was slowly drawing to an end. An attempt to re-institute it in 1703 was resisted by its Ottoman members who coveted its military and civilian posts. Finally in the early part of Ahmet III’s reign, the practice of devşirme was abolished.