The Ottoman Empire had an elaborate system of military slavery. This system was conducted by the conscription of foreigners, rather than from local Muslim populations. The Ottoman Turks had consolidated their rule over much of Eastern Europe: in 1453, they captured the Byzantine capital of Constantinople, and in 1526, they conquered Hungary.
In order to gather soldiers, groups of Ottoman officials throughout their Balkan provinces were tasked with recruiting young, Christian boys between the ages of 12 and 20. This levy of Christian youth was known as devshirme. The Ottomans had a quota to fill in the ranks of the army.
When the officials came to villages, Christian priests would make a list of all the male children baptized there. Later they were inspected by the officials. The most physically fit of the lot were then taken away from their parents and brought to Istanbul, the capital of the Ottoman Empire. It was estimated that about 3,000 boys were taken away a year.
Ottoman law came with some strange provisions, most of them backed by religion. Their bureaucracy was open only to foreigners. In this case, it was Christian slaves who were recruited to run the affairs of government. According to the law, no Muslim could legally be enslaved, so no Muslim inhabitants could serve in higher government.
The practice of military slavery was started during the Arab Abbasid dynasty, which began in the year 750. In order to secure the reaches of their large and expanding empire, the Abbasids were unable to rely on traditionally tribal-organized forces. The solution was to create a state-level bureaucracy for a tribal-organized society. Ergo, capturing your foes and forcing them into armed service. The Ottomans later adapted this approach. The system of Janissaries is estimated to have started during the reign of sultan Murad I in 1363.
Of all the boys recruited, the top 10 percent (measured by achievement) served in the palaces of Istanbul and Edirne, where they endured intensive training in order to prepare them to serve as administrators within the Ottoman Empire.
The remaining boys were raised as Turkish-speaking Muslims and placed in the Janissary corps, an elite infantry that fought for the sultans in different military campaigns throughout Europe and Asia. Meanwhile, the palace recruits were trained under eunuch supervision for a total of 2 to 8 years. The finest students would received further training in Tapkapi, the sultan’s official residence. There they learned the Koran, as well as how to speak fluently in Arabic, Persian, and Turkish. Other areas, such as music, calligraphy, and mathematics were also instructed.
These warriors-to-be would also receive formal training in horsemanship, archery, and weapons. For all the infantry Janissaries, there were also those who would serve in the household cavalry, or sipahi.
If you worked hard as a Janissary, you rise up the ladder to become a general, vizier (senior official), provincial governor, or even the grand vizier, an office that was second only to the sultan. The position of sultan, however, was restricted from them. The Ottomans still wanted to exercise a degree of control over their foreign administrators, which is why they reserved the highest office for themselves. After providing service in the sultan’s household, many Janissaries were granted estates where they could settle and collect taxes from the local inhabitants.
The enslavement was not restricted to only Christian boys. Oftentimes young girls were bought and sold as well. Once acquired, much like chattel, they would serve as wives and concubines for the Ottoman officials. As a result, there was intermixing. Some sultans were even the children of slave mothers.
Being a Janissary, though rewarding in some regards, came with its limitations. One was that neither their offices or estates were considered private property. They could not sell them or pass them down to children. The Janissaries were often mandated to live celibate lives, but a few would go on to have families with some of the slave girls. The biggest restraint was that the sultan, at all times, had control of their lives, and could do such things as reward them with offices, demote, and even execute them at will.
Because of their close bonds with their masters, the Janissaries proved to have a powerful influence within the Ottoman Empire. Several provisions under the law gave them additional rights over time. During the 16th century, sultans Selim the Grim and Suleiman the Magnificent granted Janissaries the permission to marry, and later start families. Under Selim II, their sons were allowed to enter military service; during the reign of Murad IV, the devshirme recruitment system abolished once and for all.
With more power came less responsibility. The Janissaries began to grow self-interested as they became more autonomous, detaching themselves from the sultans. They developed closer ties to the civilian population, forming their own independent trade and commercial ventures.
But their biggest threat was to the government at large. Many times the Janissaries, upset with the administration, would riot and mutiny, forcing their sultans, who they had considerable influence over, to dismiss certain officials. They even went as far as setting fire to Constantinople on several occasions.
The corruption of the Janissaries came to threaten the stability of the Ottoman Empire. About 12 sultans were dethroned, most of them murdered. The Janissaries simply replaced them with more favorable ones. In that way they were like the Roman Praetorian Guard, deposing and unseating rulers at will. The comparison seems most appropriate.
When one of the sultans, Selim III, tried to replace them with a more disciplined force, the Janissaries dethroned him, like all their other opponents. It took the work of another sultan, Mahmud II, to to effectively end their rule.
When Mahmud II organized a a force of troops, the eshkenjis, to oppose the Janissaries, they rose in revolt. Like before, they turned their mutinous ire on the city of Constantinople, robbing and pillaging. After this, war was declared against them. After refusing a last minute appeal to surrender, the Janissaries faced cannon fire. Afterwards, their barracks were burned to the ground. Many were either killed or exiled. This revolt and its aftermath became known as the Auspicious Incident.
After that the Janissaries were permanently disbanded. The foreign fighting force of the Ottoman empire, having existed for more than 400 years, came to an abrupt end. In an ironical twist of historical fate, the Ottoman system of military slavery, at first well-controlled, ended up becoming too much for its masters to control. When power bloomed to the point of persecution, the Ottomans responded in kind. With the sword. And extinction of the same tyranny they had helped to install.
Fukuyama, Francis The Origins of Political Order (2011)