History of Poland, a highly cultured, powerful, Roman Catholic empire in east central Europe in the late Middle Ages, Poland was partitioned by its neighbours in the late 18th century but re-emerged as an independent state at the end of World War I.
United under the Piast dynasty by the late 10th century, the Christian lands constituting Poland became a kingdom (1024—25) and afterward engaged in a series of struggles that involved territorial changes as well as the development of separatist tendencies among its provinces. Boleslaw III the Wry-Mouthed (ruled 1102—38) divided Poland among his sons, causing his lands to remain disunited until Wiadyslaw I the Short restored the kingdom (1320). Casimir III, the last Piast ruler (ruled 1330—70), then transformed Poland into a powerful, cosmopolitan empire, which in 1385 formed a dynastic union with Lithuania and came under the rule of the Jagiellon dynasty for the next two centuries.

By the late 1 5th century Poland’s territory stretched from the Baltic to the Black Sea, its influence extended over the kingdom of Bohemia and Hungary, which were ruled by other members of the Jagiellon dynasty. In the 16th century, it was threatened by the increase of its nobles’ power as well as by the Ottoman Turks and Muscovy (Russia). Although it entered into a formal union with Lithuania that created an indivisible Royal Republic (1569) in which the nobility elected the king and held the exclusive right to make laws, it lost its territories on the Baltic and in the Ukraine as a result of lengthy wars with Sweden, Russia, and the Turks (17th century); it also suffered from a deterioration in its political system, manifested by the right of any delegate to the Diet (Sejm) to veto legislation and from social disturbances caused by the suppression of non- Catholic religious groups during the Counter Reformation.
Devastated by the Great Northern War (1700—21), Poland fell under Russia’s dominating influence and was powerless when Russia, Prussia, and Austria divided it among themselves in three successive partitions (1772, 1793, 1795). The Poles retained a sense of national identity, however, staged several revolts against their foreign rulers during the 19th century, and at the end of World War I re-established an independent republic. From 1926 to 1935 the country was under the dictatorial rule of Pilsudski, and in 1939 it was divided between Germany and the U.S.S.R. After World War II, Poland’s eastern and western borders were both shifted westward, and in 1952 it became a Communist People’s Republic. articlezap