As Janissaries became aware of their own importance they began to desire a better life. By the early 18th century Janissaries had such prestige and influence that they dominated the government. They could mutiny and dictate policy and hinder efforts to modernize the army structure. They could change Sultans as they wished through palace coups. They made themselves landholders and tradesmen. They would also limit the enlistment to the sons of former Janissaries who did not have to go through the original training period in the acemi oğlan, as well as avoiding the physical selection, so of lesser military value.
When Janissaries could practically extort money from the Sultan and business and family life replaced martial fervour, their effectiveness as combat troops decreased. The northern borders of the Ottoman Empire slowly began to shrink southwards after the second Battle of Vienna in 1683.
In 1449 they revolted for the first time, demanding higher wages, which they obtained. The stage was set for a decadent evolution, like the Praetorian Guard which had proved the greatest threat to Roman emperors, rather than an effective protection. After 1451, every new Sultan felt obligated to pay each Janissary a reward and raise his pay rank. Sultan Selim II gave janissaries permission to marry in 1566, undermining the exclusivity of loyalty to the dynasty.
By 1622, the Janissaries were a "serious threat" to the stability of the Empire.[11] Through their "greed and indiscipline", they were now a law unto themselves and, against modern European armies, ineffective on the battlefield as a fighting force. [11] In 1622, the teenage sultan, Osman II, came to the throne, determined to curb Janissary excesses and outraged at becoming "subject to his own slaves".[11] In the spring, hearing rumours that the sultan was preparing to move against them, the Janissaries revolted and took the sultan captive, imprisoning him in the notorious Seven Towers: he was murdered shortly afterwards.[11]
