A significant number of Bošnjani, Bosnian dualists and Slavic tribes living in The Bosnian kingdom converted to Islam after the conquest by the Ottoman Empire in the second half of the 15th century, giving it a unique character within the Balkan region. This conversion appears to have been not sudden but a gradual process through coercions based on various rules imposed by the Ottomans — it took more than a hundred years for the number of Muslims to become the majority religion.
Several factors appear to have been behind this process. Most important was that Christianity had relatively shallow roots in Bosnia prior the Ottoman domination. Bosnia lacked a strong Christian church organization to command a strong following—the result of a scarcity of priests and competition among the Orthodox and Roman Catholic Churches and the indigenous and schismatic Bosnian Church, which collapsed shortly before the Ottomans arrived. This left most Bosnians religiously unengaged and receptive to the appeal of Islam’s sophisticated and dynamic institutions. This receptiveness was aided by the development among many Bosnians of a kind of folk Christianity centered on various practices and ceremonies that was adaptable to a form of folk Islam popular at the time of the invasion.
Always on a purely religious ground, it is also said, by the orientalist Sir Thomas Arnold for instance, that because of Bogomilism, a major heresy in the region at the time, oppressed by the Catholics and against whom Pope John XXII even launched a Crusade in 1325, the people were more receptive to the Turks. In fact, in the Bogomilian tradition, there were several practices that resembled Islam: they rejected the worship of Virgin Mary, repudiated the Cross as a religious symbol, they considered it as idolatry to bow down before religious images, relics or saints, and even prayed five times a day (reciting the Lord's Prayer.)
Economic and social gain was also an incentive to become a Muslim: conversion to Islam conferred economic and social status. Under the feudal system imposed by the Ottomans, only those who converted to Islam could acquire and inherit land and property, which accorded them political rights and status usually denied to non-Muslims. A number of Christian nobles, however, were able to retain their estates early on in the Ottoman rule by fighting on behalf of the Empire, suggesting that holding on to their property was not a major incentive for early conversions to Islam. At a lower socioeconomic level, most new converts to Islam were able to turn their holdings into freehold farms. At the bottom of the socioeconomic ladder were the serfs, who constituted the majority of the population and were predominantly Christians. In addition, only Muslims could hold positions in the Ottoman state apparatus, which conferred special privileges and a much higher standard of living. Muslims also enjoyed legal privileges: Christians could not sue Muslims and their testimony could not be used against Muslims in court.
The gradual conversion of many Bosnians to Islam proceeded at different rates in various areas and among different groups. Conversion to Islam was more rapid in urban areas, which were centers of learning and of the Ottoman administration, than in the countryside. Merchants found it advantageous to convert to Islam because they gained greater freedom of movement and state protection for their goods as Muslims. Many professional soldiers also converted to Islam to ensure more rapid promotion.
The various advantages and privileges that were reserved for Muslims and the large number of conversions they encouraged among the native population led to the emergence over time of a largely local Muslim ruling class that dominated political and economic power in Bosnia and Herzegovina.