Islam is the most widespread religion in Bosnia and Herzegovina. It was introduced to the local population in the 15th and 16th centuries as a result of the Ottoman conquest of Bosnia and Herzegovina. Muslims comprise the single largest religious community in Bosnia and Herzegovina (51%) (the other two large groups being Eastern Orthodox Christians (31%), almost all of whom identify as Serbs, and Roman Catholics (15%), almost all of whom identify as Croats. Another estimate done by PEW Research states that 52% of the population is Muslim, 35% Orthodox and only 8% Catholic. Almost all of Bosnian Muslims identify as Bosniaks; until 1993, Bosnians of Muslim culture or origin (regardless of religious practice) were defined by Yugoslav authorities as Muslimani (Muslims) in an ethno-national sense (hence the capital M), though some people of Bosniak or Muslim backgrounds identified their nationality (in an ethnic sense rather than strictly in terms of citizenship) as "Yugoslav" prior to the early 1990s. A small minority of non-Bosniak Muslims in Bosnia and Herzegovina include Albanians, Roma and Turks. Albeit traditionally adherent to Sunni Islam of the Hanafi school of jurisprudence, a 2012 survey found 54% of Bosnia and Herzegovina's Muslims to consider themselves just Muslims, while 38% told that they are Sunni Muslims. There is also a small Sufi community, located primarily in Central Bosnia. A small Shia Muslim community is also present in Bosnia. Almost all Muslim congregations in Bosnia and Herzegovina refer to the Islamic Community of Bosnia and Herzegovina as their religious organisation. The Constitution of Bosnia and Herzegovina guarantees freedom of religion, which is generally upheld throughout the country. History The Ottoman era Islam was first introduced to the Balkans on a large scale by the Ottomans in the mid-to-late 15th century who gained control of most of Bosnia in 1463, and seized Herzegovina in the 1480s. Over the next century, the Bosnians – composed of native Christians and Slavic tribes living in the Bosnian kingdom under the name of Bošnjani – were converted to Islam in great numbers during the Islamization of Bosnia under Ottoman rule. During the Ottoman era the name Bošnjanin was definitely transformed into the current Bošnjak ('Bosniak'), with the suffix -ak replacing the traditional -anin. By the early 1600s, approximately two thirds of the population of Bosnia were Muslim. Bosnia and Herzegovina remained a province in the Ottoman Empire and gained autonomy after the Bosnian