The Serbs were converted to Christianity not long after their arrival in the Balkans, before the Great Schism split the Christian Church into rival Latin-speaking (Roman Catholic) and Greek-speaking (Eastern Orthodox) Churches. During the early Middle Ages, the religious allegiance of the Serbs was divided between the two churches. In the ninth and tenth centuries, Orthodoxy made great inroads into Eastern Europe. This work was made possible by the work of the Byzantine saints Cyril and Methodius.Some of the disciples, namely Saint Clement of Ohrid, and Saint Naum In a short time the disciples of Cyril and Methodius managed to prepare and instruct the future Slav clergy into the Glagolitic alphabet and the biblical texts and in AD 893, The work of the Thessaloniki brothers Cyril and Methodius and their disciples had a major impact to Serbs as well. However, they accepted Orthodoxy collectively by families and by tribes (in the process between the 7th and the 9th century). In commemoration of their baptisms, each Serbian family or tribe began to celebrate an exclusively Serbian custom called Slava in a special way to honor the Saint on whose day they received the sacrament of Holy Baptism. It is the most solemn day of the year for all Serbs of the Orthodox faith and has played a role of vital importance in the history of the Serbian people. Slava is actually the celebration of the spiritual birthday of the Serbian people which the Church blessed and proclaimed it a Church institution.
The various Serbian principalities were united ecclesiastically in the early 13th century by Saint Sava, the son of the Serbian ruler and founder of the Serbian medieval state Stefan Nemanja and brother of Stefan Prvovencani, the first Serbian king. Sava persuaded the Ecumenical Patriarch of Constantinople to establish the Church in Serbia as an autocephalous body, with Sava himself as its archbishop, consecrated in 1219. This sealed Orthodox Christian supremacy in the Serbian realm, which was up then divided between Catholicism and Orthodoxy. The status of the Serbian Orthodox Church grew along with the growth in size and prestige of the medieval kingdom of Serbia. After King Stefan Dušan assumed the imperial title of tsar, the Archbishopric of Peć was correspondingly raised to the rank of Patriarchate in 1346. In the century that followed, the Serbian Church achieved its greatest power and prestige. In 1459, the Ottoman Empire conquered Serbia and made much of the former kingdom a pashaluk. Although many Serbs converted to Islam, most continued their adherence to the Serbian Orthodox Church). The Church itself continued in existence throughout the Ottoman period, though not without some disruption. After the death of Patriarch Arsenios II in 1463, a successor was not elected. The Patriarchate was thus de facto abolished, and the Serbian Church passed under the jurisdiction of the Ecumenical Patriarchate. The Serbian Patriarchate was restored in 1557 by the sultan Suleiman the Magnificent, much thanks to the famous Mehmed-paša Sokolović, when Macarios, his brother or cousin, was elected Patriarch in Peć. Great Serb Migrations, led by the Serbian Orthodox Patriarch Arsenije III Carnojevic, 17th centuryThe restoration of the Patriarchate was of great importance for the Serbs because it helped the spiritual unification of all Serbs in the Turkish Empire. After consequent Serbian uprisings against the Turkish occupiers in which the Church had a leading role, the Turks abolished the Patriarchate once again in 1766. The Church remained once more under the jurisdiction of the Ecumenical Patriarch of Constantinople. This period of so called "Phanariots" was a period of great spiritual decline because the Greek bishops had very little understanding of their Serbian flock. During this period, many Christians across the Balkans converted to Islam to avoid severe taxes imposed by the Turks in retaliation for uprisings and continued resistance. Many Serbs migrated with their hierarchs to Habsburg Monarchy where they had been granted autonomy. The seat of the archbishops was moved from Peć to Karlovci. The new Serbian Metropolitanate of Karlovci became a patriarchate in 1848. The church's close association with Serbian resistance to Ottoman rule led to Serbian Orthodoxy becoming inextricably linked with Serbian national identity and the new Serbian monarchy that emerged from 1817 onwards. The Serbian Orthodox Church in Serbia finally regained its independence and became autocephalous in 1879, the year after the recognition by the Great Powers of Serbia as an independent state. This church was known as the Metropolitanate of Belgrade, thus in the end of the 19th century and beginning of the 20th century, two separate Serbian Churches existed - the Patriarchate of Karlovci in the Habsburg Monarchy and the Metropolitanate of Belgrade in the Kingdom of Serbia. The Cetinje Metropolitanate held successorship to the Serb Patriarchate in Pec, its Vladikas were "Exarchs of the Pec Throne" The Serbian Orthodox Church (Serbian: Srpska Pravoslavna Crkva; СПЦ / SPC) or the Church of Serbia is one of the autocephalous Orthodox Christian churches. It is the second oldest Slavic Orthodox Church in the world, as well as the westernmost Eastern Church in Europe. It exercises jurisdiction over Orthodox Christians in Serbia and surrounding Slavic and other lands, as well as exarchates and patriarchal representation churches around the world. The Patriarch of Serbia serves as first among equals in his church; the current patriarch is His Holiness Pavle. The Serb Patriarch's full title is "Archbishop of Peć, Metropolitan of Belgrade and Karlovci, and Patriarch of the Serbs."</p>