Janissaries were the elite army of the Sultan and a potent political force in the Ottoman empire. They were gathered by means of a titheing system. Christian lands occupied by the Ottomans where required to give two boys from every village to the Sultan. These boys were trained rigorously, educated and converted to Islam. The Janissary system was a meritocracy where the ablest would move up the ranks of government service. In fact, the highest position in the government, the Grand Vizier, who was the administrative ruler of the empire, came from the ranks of the Janissaries. Most prized were Serbs, Bulgarians and Albanians who were tough and fierce. At one point at the height of the empire under the ablest Sultan, Suleyman the Magnificent, the Vizier was Bosnian. The Janissaries later became a powerful powerful political force but equally corrupt. They could actually overthrow a Sultan as they did on occassion. The Sultans tied to abolish the system in the later years but found them too strong. Eventually, one of the Sultans formed another army and one night ambushed and slaughtered the whole Janissary army in Topkapi finally putting an end to the system.