The Religious Dimension of Poland's Relations with Its Eastern Neighbours (Report‪)‬

The countries of Central and Eastern Europe have developed long-standing ties. Relations between the peoples of Poland, Lithuania, Belarus and Ukraine have been particularly close. Poles, Belarusians and Ukrainians are Slavs, speaking closely related languages. Belarusians and Ukrainians share a heritage in Kievan Rus, an early Slavic state. For much of the last millennium, most of the territory which now forms Poland, Lithuania, Belarus and Ukraine was united in a loose political entity divided in two parts: the Kingdom of Poland and the Grand Duchy of Lithuania. Ukraine and Belarus first came into existence as independent states in the last century--briefly at the end of World War I, and again, more permanently, when the Soviet Union dissolved in 1991. The main religions in the area are Roman Catholicism (in Poland and Lithuania), Eastern Orthodox Christianity (in Ukraine and Belarus) and Greek Catholicism (in western Ukraine). The Greek Catholic (or Uniate) Church dates from the 1595 Union of Brest, under which much of the Ruthenian church broke away from the Orthodox communion and accepted the Roman Pope as spiritual leader, while retaining eastern Christian religious rites. The 1569 Polish-Lithuanian Union of Lublin eventually led to the nobility and much of the urban population throughout what later became Belarus and western Ukraine becoming Roman Catholic. In these lands, this process of Catholicisation was also, in large measure, a process of polonisation. Within a century of the union the landed class throughout the lands of the Polish-Lithuanian Commonwealth was Polish in language and culture. Until World War II, Judaism was also an important part of the region's religious mosaic.