Silesia ( or ; ; ; Silesian German: Schläsing; ; Silesian: Ślůnsk ; ) is a region of Central Europe now located mostly in Poland, with small parts in the Czech Republic and Germany. It has about 40,000 km2 and almost 8,000,000 inhabitants. Silesia is located along the Odra river. It consists of Lower Silesia and Upper Silesia.
The region is rich in mineral and natural resources and includes several important industrial areas. Silesia's largest city is Wrocław. The biggest metropolitan area is the Upper Silesian metropolitan area, the centre of which is Katowice. Parts of the Czech city of Ostrava fall within the borders of Silesia.
Silesia's borders and national affiliation have changed over time, both when it was a hereditary possession of noble houses and after the rise of modern nation-states. The first known states to hold power there were probably those of Greater Moravia at end of the 9th century and Bohemia early in the 10th century. In the 10th century Silesia was incorporated into the early Polish state, and after its division in the 12th century became Piast duchy. In the 14th century it became a constituent part of the Bohemian Crown Lands under the Holy Roman Empire, which passed to the Austrian Habsburg Monarchy in 1526.
Most of Silesia was conquered by Prussia in 1742, later becoming part of the German Empire, the Weimar Republic and Nazi Germany up to 1945. After World War I the easternmost part of this region, i.e. an eastern strip of Upper Silesia, was awarded to Poland by the Entente Powers after rebellions by Silesian Polish people and the Upper Silesian plebiscite. In 1945, after World War II the bulk of Silesia was transferred to Polish jurisdiction by the Potsdam Agreement of the victorious Allied Powers and became part of Poland. The remaining former Austrian parts of Silesia were partitioned to Czechoslovakia, and are today part of the Czech Republic. The small Lusatian strip west of the Oder-Neisse line, which belonged to Silesia since 1815, remained in Germany.
Most inhabitants of Silesia today speak the national languages of their respective countries (Polish, Czech). The population of Upper Silesia is native (with many immigrants from Poland who came in 19th century), while the Lower Silesia was settled by Germans before 1945. There is an ongoing debate whether a local Silesian speech should be considered a Polish dialect or a separate language. There also exists a Silesian German or Lower Silesian language, although this form of German is almost extinct.
In the 4th century BC Celts entered Silesia, settling around Mount Ślęża near modern Wrocław, Oława, and Strzelin. Germanic Lugii tribes were first recorded within Silesia in the 1st century. Slavic peoples arrived in the region around the 7th century, and by the early 9th 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 10th 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 claimed goals of Nazi occupation, particularly in Upper Silesia, was the extermination of those who Nazis viewed as subhuman, namely 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 line 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 regions. 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 and brutality in occupation, 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.