Volhynia (vŏlĭˈnyə) [key], Ukr. and Rus. Volyn, Pol. Wołyń, historic region, W Ukraine, around the headstreams of the Pripyat and Western Bug rivers in an area of forests, lakes, and marshlands. One of the oldest Slavic settlements in Europe, it derived its name from the extinct city of Volyn or Velyn, said to have stood on the Western Bug. Volhynia's early history from c.981 coincides with that of the duchies of Volodymyr (see Volodymyr-Volynskyy) and Halych. After the disintegration (c.1340) of the grand duchy of Halych-Volodymyr, Volhynia was divided (c.1388) between Poland (western part) and Lithuania (eastern part). With the Polish-Lithuanian union of 1569, Volhynia became a quasi-autonomous province of Poland. During the second and third partitions of Poland (1793, 1795), Volhynia passed to Russia and was made (1797) a province. In 1921 the Treaty of Riga returned W Volhynia to Poland, but the rest passed to Ukraine. Poland ceded its section of Volhynia to the USSR in 1939, and the Soviet-Polish border agreement of 1945 confirmed it as a Soviet possession. In 1943–44 the region was the scene of ethnic massacres in which some 100,000 Poles died and some 20,000 Ukrainians were killed in revenge. This section constitutes the Volyn region, a rich agricultural lowland and coal-mining area.