Silesia ( or ; ; ; Silesian German: Schlesien; ; Silesian: Ślůnsk ; ) is a region of Central Europe now located mostly in Poland, with smaller parts in the Czech Republic and Germany. Silesia is divided into Lower Silesia and Upper Silesia.
In the fourth century BC Celts entered Silesia, settling around Mount Ślęża near modern Wrocław, Oława, and Strzelin. Germanic tribes were first recorded within Silesia in the first century . Slavic peoples arrived in the region around the seventh century, and by the early ninth century their settlements had stabilized. Local Slavs started to erect boundary structures like the Silesian Przesieka and the Silesia Walls. The eastern border of Silesian settlement was situated to the west of the Bytom, and east from Racibórz and Cieszyn. East of this line dwelt a closely related Slav tribe, the Vistulans. Their northern border was in the valley of the Barycz river, north of which lived the Polans.
The first known states in Silesia were Greater Moravia and Bohemia. In the tenth century, the Polish ruler Mieszko I of the Piast dynasty incorporated Silesia into the Polish state. During the Fragmentation of Poland, Silesia, as well as the rest of the country, was divided among many independent duchies ruled by various Silesian dukes. During this time, German cultural and ethnic influence increased as a result of immigration from German-speaking parts of the Holy Roman Empire. In 1178, parts of the Duchy of Kraków around Bytom, Oświęcim, Chrzanów and Siewierz were transferred to the Silesian Piasts, although their population was primarily Vistulan and not of Silesian descent.
Between 1289 and 1292 Bohemian king Wenceslaus II became suzerain of some of the Upper Silesian duchies. It wasn't until 1335, however, that Polish kings renounced their hereditary rights to Silesia. The province became part of the Bohemian Crown under the Holy Roman Empire, and passed with that crown to the Habsburg Monarchy of Austria in 1526.
In the 15th century several changes were made to Silesia's borders. Parts of the territories which had been transferred to the Silesian Piasts in 1178 were bought by the Polish kings in the second half of the 15th century (the Duchy of Oświęcim in 1457; the Duchy of Zator in 1494). The Bytom area remained in the possession of the Silesian Piasts, even though it was a part of the Diocese of Kraków. The Duchy of Crossen was inherited by the Margraviate of Brandenburg in 1476, and with the renunciation of King Ferdinand I and the estates of Bohemia in 1538, became an integral part of Brandenburg.
In 1742, most of Silesia was seized by King Frederick the Great of Prussia in the War of the Austrian Succession, becoming the Prussian Province of Silesia; consequently, Silesia became part of the German Empire when it was proclaimed in 1871.
After World War I, Upper Silesia was contested by Germany and the newly independent Second Polish Republic. The League of Nations organized a plebiscite to decide the issue in 1921. It resulted in 60% of votes being cast for Germany and 40% for Poland. Following the third Silesian Uprising (1921), however, the easternmost portion of Upper Silesia (including Katowice), with a majority ethnic Polish population, was awarded to Poland, becoming the Silesian Voivodeship. The Prussian Province of Silesia within Germany was then divided into the provinces of Lower Silesia and Upper Silesia. Meanwhile Austrian Silesia, the small portion of Silesia retained by Austria after the Silesian Wars, was mostly awarded to the new Czechoslovakia (becoming known as Czech Silesia), although most of Cieszyn and territory to the east of it went to Poland (see Zaolzie).
Polish Silesia was among the first regions invaded during Germany's 1939 attack on Poland. One of the goals of Nazi occupation, particularly in Upper Silesia, was to exterminate those who Nazis viewed as subhuman Jews and ethnic Poles. The Polish and Jewish population of Silesia was subjected to genocide involving ethnic cleansing and mass murder, while German colonists were settled in pursuit of Lebensraum. Two thousand Polish intellectuals, politicians and businessmen were murdered in the "Intelligenzaktion Schlesien" in 1940 as part of a Poland wide Germanization program. Silesia also housed one of the two main wartime centers where medical experiments were conducted on kidnapped Polish children by Nazis.
The Potsdam Conference of 1945 concluded that the Oder-Neisse would be the official border between Germany and Poland. Millions of Germans in Silesia, either fled or were expelled, and were replaced later by Polish population settled from other region. Furthermore, the newly formed Polish United Workers' Party created a Ministry of the Recovered Territories that claimed half of the available arable land for state-run collectivized farms. Many Silesian residents not only resented the Germans for their invasion in 1939, but now also the newly formed Polish communist government for their population shifting and interference in agricultural, as well as industrial, affairs.
The administrative division of Silesia within Poland has changed several times since 1945. Since 1999 it has been divided between Lubusz Voivodeship, Lower Silesian Voivodeship, Opole Voivodeship, and Silesian Voivodeship. Czech Silesia is now part of the Czech Republic, forming the Moravian-Silesian Region and the northern part of the Olomouc Region. Germany retains the Silesia-Lusatia region (Niederschlesien-Oberlausitz or Schlesische Oberlausitz) west of the Neisse, which is part of the federal state of Saxony.