The Catholic Church is the fourth largest religious congregation in Bulgaria, after Eastern Orthodoxy, Islam and Protestantism. Its roots in the country date to the Middle Ages and are part of the worldwide Catholic Church, under the spiritual leadership of the Pope in Rome. Location and number In the Bulgarian census of 2011, a total of 48,945 people declared themselves to be Catholics, up from 43,811 in the previous census of 2001 though down as compared to 53,074 in 1992. The vast majority of the Catholics in Bulgaria in 2001 were ethnic Bulgarians and the rest belonged to a number of other ethnic groups such as Croatians, Italians, Arabs and Germans. Bulgarian Catholics live predominantly in the regions of Svishtov and Plovdiv and are mostly descendants of the heretical Christian sect of the Paulicians, which converted to Catholicism in the 16th and 17th centuries. The largest Catholic Bulgarian town is Rakovski in Plovdiv Province. Ethnic Bulgarian Catholics known as the Banat Bulgarians also inhabit the Central European region of the Banat. Their number is unofficially estimated at about 12,000, although Romanian censuses count only 6,500 Banat Bulgarians in the Romanian part of the region. Bulgarian Catholics are descendants of three groups. The first were converted Paulicians from the course of the Osam river (between Stara Planina and the Danube) and around Plovdiv are the second (and largest) group, while the third (and most limited) one is formed by more recent Eastern Orthodox converts. Geographical distribution Most Catholics live in the province of Plovdiv (19,502 Catholics), followed by the city of Sofia (5,572 Catholics) and the provinces of Pleven (5,164 Catholics) and Veliko Tarnovo (3,276 Catholics) History Bulgarian Empire Although the presence of Catholicism existed during the reign of Roman Empire in Balkan Peninsula, Catholic missionaries first tried to convert the Bulgarians during the reign of Tsar Boris I in the middle of the 9th century. They were unsuccessful, and Boris I led the Bulgarians in their conversion to Eastern Christianity. In 1204 the Bulgarian Tsar Kaloyan (1197-1207) formed a short-lived union between the Catholic Church and the Bulgarian Orthodox Church as a political tactic to balance the religious power of the Byzantine Empire. The union ended when the Bulgarian Patriarchate was reestablished in 1235 during the council of Lampsacus. Ottoman rule Nonetheless, Catholic missionaries renewed their interest in Bulgaria during the 16th century, after the Council of Trent, when they