Christianity is the predominant religion in Serbia. The Constitution of Serbia defines it as a secular state with guaranteed religious freedom. Eastern Orthodox Christians with 6,079,396 members, comprise 84.5% of country's population. The Serbian Orthodox Church is the largest and traditional church of the country; adherents of it are overwhelmingly Serbs. Public schools in Serbia allow religious teaching, most commonly with the Serbian Orthodox Church. Serbian public holidays include the religious celebrations of Eastern Orthodox Christians. Other Orthodox Christian communities in Serbia include Montenegrins, Romanians, Macedonians, and Bulgarians. The Catholic Church is prominent in north Vojvodina amongst the Hungarian minority. Protestantism is most largely found in Slovak populations within Bački Petrovac and Kovačica. Christianity first arrived in Serbia in the 9th century. It became state-religion in the 9th century when Serbia began to identify as a Christian country. In a 2011 census, 91.22% of Serbians identified as Christian.[citation needed]