ENThe Orthodox Church has hundreds of years of history in the Polish Commonwealth. Its beginnings date back to the period of the formation of the Polish state in the 9th century. The subjection of the Vislanes tribe’s territories to Great Moravia resulted in the Christianization of Lesser Poland as early as the end of the 9th century. Therefore the Cyrillo-Methodian rite had been widespread in Polish territories long before the adoption of Christianity by Duke Mieshko I in 966. Within the next centuries the Orthodox believers subject to the jurisdiction of Constantinople made up a major part of the inhabitants of the Polish Commonwealth, forming the majority of the population in its eastern parts. During the reign of Mieshko I, the Chervinskie Castle-towns constituted part of his state. The incorporation of the Chervinskie Castle-towns by Boleslav the Brave in 1018 initiated a constant presence of the Orthodox Church within the borders of the State of Poland. The princes of Halich-Volhynia made a particular contribution to the development of the Orthodox Church in the eastern territories of Poland. In consequence of the transfer of the seat of the metropolitan of Kyiv from Kyiv to Vlodimir on the Klazma, Duke of Halich George I, in 1303, received permission from the patriarchate of Constantinople (to which the Orthodox Church in the Rhutenian territories was jurisdically subjected) to establish a separate metropolitanate. The metropolitanate of Halich embraced the bishoprics of Volodymyr, Peremysl, Lutsk, Turau and Kholm. At the same time, as a result of efforts made by dukes of Lithuania, the Lithuanian metropolitanate was called into being with the seat in Novahradak. The establishment of the new Orthodox Church structure was connected with the plans of the subjugation of Rhutenian territories by Lithuania, and with leading to a break of ties with the metropolitanate of Kyiv, being under the influence of dukes of Moscow.Due to their activities, both the metropolitanates – the Lithuanian one and that of Halich – were dissolved in 1330. Their reestablishing took place under the rules of Olgerd in Lithuania in 1350. In 1371, the metropolitanate of Halich was incorporated into the Lithuanian one. The dissolution of the Halich metropolitanate by the dukes of Lithuania was connected with the annexation of Halich Ruthenia to the Crown in 1366. Casimir the Great’s death (1370) cancelled the plans for the establishment of an independent Orthodox Church structure within Poland. The Union of Krevo (1386) made the Orthodox Church in the Crown and in the Grand Duchy of Lithuania find itself under the common jurisdiction of the Lithuanian metropolitans (nominally of Kyiv-Halich). At the beginning of the 15th century, the division of the Orthodox Church in the Ruthenian territories finally ended. The structure being monolithic until then, was divided into the Lithuanian and Vlodimir-Suzdal parts. The dividing line between the two metropolitanates ran along the state borders between the Grand Duchy of Lithuania and the Duchy of Moscow. In 1415 Greory Tsamblak was elected metropolitan of Lithuania (of Kyiv-Halich) and Fotsius – metropolitan of Moscow. In 1458, metropolitans of Moscow officially renounced their title to the metropolitanates of Kyiv. From 1458 to the Union of Brest (1596), the Orthodox Church in the Ruthenian territories of the Polish-Lithuanian state had its separate structure (the Metropolitanate of Kyiv-Halich), hierarchically subordinated to the patriarchate of Constantinople.Until the mid- to 16th century, the dependence on Constantinople was limited to a formal confirmation and blessing of a new metropolitan by the patriarch. Only before the Union of Brest, the patriarchate made efforts aimed at tighter subordination of the Ruthenian church in Poland to itself. Loose dependence of the Orthodox Church on the patriarchate was not accompanied by the increase in importance of the Ruthenian hierarchy, as at the same time the church was subordinated to the superior authority of the king or grand duke, who took over some juridical powers from a patriarch, particularly those concerning the appointment of metropolitans and bishops. As regulated by the canon law, the synod of bishops elected a metropolitan, who was later confirmed by the patriarch. From 1480, by king’s order, it became customary for the bishops’ synod to elect metropolitans with the participation of laymen. Kings and lay magnates did not always conform to canon requirements, tradition or the needs of the Orthodox Church. The Orthodox Church had a significant influence on the religiousness and customs of the whole Commonwealth. At the beginning of the 16th century, the organisational structure of the Orthodox Church in Poland achieved its final shape. In the 16th century, the metropolitan possessed an official title of the archbishop metropolitan of Kyiv, Halich, and of all Rus. He did not usually reside in Kyiv, but in the northern part of his diocese, in Novahradak or in Vilnyus. The Kyiv Metropolitanate governed six dioceses, seven of which lay within the boundaries of the Grand Duchy of Lithuania (Kyiv, Polatsk-Vitebsk, Smolensk- Seversk, Chernihiv-Bransk, Turov-Pinsk, Lutsk-Ostroh, and Volodymyr-Brest) and three in Ruthenian territories of the Polish Crown (Khelm-Belzsk, Przemysl- Samborsk, and Halych). ... Keywords: Autocephaly, Metropolitanate of the Kyiv, Metropolitanate of the Halych, Metropolitanate of the Lithuania, Orthodox Church.