Islam in the Ottoman Empire
Islam was the official religion of the Ottoman Empire. The highest position in Islam, "caliphate", was claimed by the sultan, after the defeat of the Mamluks which was established as Ottoman Caliphate. The Sultan was to be a devout Muslim and was given the literal authority of the Caliph. Additionally, Sunni clerics had tremendous influence over government and their authority was central to the regulation of the economy. Despite all this, the Sultan also had a right to decree, enforcing a code called Kanun (law) in Turkish. Additionally, there was a supreme clerical position called the Sheykhulislam ("Sheykh of Islam" in Arabic). Minorities, particularly Christians and Jews but also some others, were mandated to pay the jizya, the poll tax as mandated by traditional Islam.
Christianity in the Ottoman Empire
There is insufficient documentation of the process of conversion to Islam in Anatolia before the mid-15th century. By that time it was about 85% complete according to an Ottoman census, although in lagged in some regions such as Trabzon. In the Balkans, the general trend of conversion started slowly in the 14th century, reached its peak in the 17th century, and gradually petered out by the end of the 18th century, with significant regional variations.