How did the Janissaries turn Christian boys into the sultan's soldiers?

The Janissaries were the sultan's own soldiers, and they began with a harsh bargain. Under the devshirme, "collecting", often called the child levy or blood tax, Ottoman officials took Christian boys, mostly from the Balkans, aged from 7 to 20, brought them to Istanbul, converted them to Islam and trained them for the Janissary infantry or for palace service. The system is first mentioned in written records in 1438, though it probably started earlier.

Why do this? Because it created a faction of soldiers and officials loyal to the sultan, a counterweight to the Turkish nobility, who sometimes opposed him. Janissaries were paid regular salaries, unlike typical slaves, and were forbidden to marry until retirement or to engage in trade.

Talent could take a boy far. Recruits were sorted by ability and could rise on merit, and the best trained for the highest posts in the empire. Sokollu Mehmed Paşa, a Bosnian Serb, became Grand Vizier, served three sultans and was de facto ruler of the empire for more than 14 years. One historian, Dimitri Kitsikis, argues that many Bosnian Christian families were even willing to comply, for the chance of social advancement.

But the cost was real. Children were taken by force, and locals resented it. A Serbian called Konstantin Mihailović, abducted in his youth, wrote in his memoir that he saw nothing "prestigious" or "lucrative" in becoming a janissary.

The weapon turned on its masters. The Janissaries first revolted in 1449, demanding higher wages. By the 17th century civilians were buying their way into the corps, and as European armies modernised, the corps became a reactionary force that resisted all change. In 1826 Sultan Mahmud II abolished the Janissaries in the Auspicious Incident, in which 6,000 or more were executed.