Silesia[a] (see names below) is a historical region of Central Europe that lies mostly within Poland, with small parts in the Czech Republic and Germany.

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, resulting in an abundance of castles, especially in the Jelenia Góra valley.

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; however, a number of duchies remained under the rule of Polish dukes from the houses of Piast, Jagiellon and Sobieski as formal Bohemian fiefdoms, some until the 17th–18th centuries.

In 1945, after World War II, most of the German-held Silesia was transferred to Polish jurisdiction by the Potsdam Agreement between the victorious Allies and became again part of Poland, although with a Soviet-installed communist regime.

As the result of the forced population shifts of 1945–48, today's inhabitants of Silesia speak the national languages of their respective countries.

The names of Silesia in different languages most likely share their etymology—Polish: Śląsk [ɕlɔ̃sk] ⓘ; German: Schlesien [ˈʃleːzi̯ən] ⓘ; Czech: Slezsko [ˈslɛsko]; Lower Silesian: Schläsing; Silesian: Ślōnsk [ɕlonsk]; Lower Sorbian: Šlazyńska [ˈʃlazɨnʲska]; Upper Sorbian: Šleska [ˈʃlɛska]; Slovak: Sliezsko; Latin, Spanish and English: Silesia; French: Silésie; Dutch: Silezië; Italian: Slesia.

[6] According to some Polonists, the name Ślęża [ˈɕlɛ̃ʐa] or Ślęż [ɕlɛ̃ʂ] is directly related to the Old Polish words ślęg [ɕlɛŋk] or śląg [ɕlɔŋk], which means dampness, moisture, or humidity.

[9] In the fourth century BC from the south, through the Kłodzko Valley, the Celts entered Silesia, and settled around Mount Ślęża near modern Wrocław, Oława and Strzelin.

Their northern border was in the valley of the Barycz River, north of which lived the Western Polans tribe who gave Poland its name.

During the Fragmentation of Poland, Silesia and the rest of the country were divided into many smaller duchies ruled by various Silesian dukes.

[13] Since the 13th century, German cultural and ethnic influence increased as a result of immigration from German-speaking states of the Holy Roman Empire.

Breslau was a center of Jewish life in Germany and an important place of science (university) and industry (manufacturing of locomotives).

Polish Silesia was among the first regions invaded during Germany's 1939 attack on Poland, which started World War II.

[16] Two thousand Polish intellectuals, politicians, and businessmen were murdered in the Intelligenzaktion Schlesien[17] 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 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.

Germany retains the Silesia-Lusatia region (Niederschlesien-Oberlausitz or Schlesische Oberlausitz) west of the Neisse, which is part of the federal state of Saxony.

Lower Silesia features large copper mining and processing between the cities of Legnica, Głogów, Lubin, and Polkowice.

[21] The region also has a thriving agricultural sector, which produces cereals (wheat, rye, barley, oats, corn), potatoes, rapeseed, sugar beets and others.

The Opole Silesia has for decades occupied the top spot in Poland for their indices of effectiveness of agricultural land use.

[30] Mountainous parts of southern Silesia feature many significant and attractive tourism destinations (e.g., Karpacz, Szczyrk, Wisła).

[34] The last Polish census of 2011 showed that the Silesians are the largest ethnic or national minority in Poland, Germans being the second; both groups are located mostly in Upper Silesia.

In the early 19th century the population of the Prussian part of Silesia was between 2/3 and 3/4 German-speaking, between 1/5 and 1/3 Polish-speaking, with Sorbs, Czechs, Moravians and Jews forming other smaller minorities (see Table 1. below).

After World War II, the religious demographics changed drastically as Germans, who constituted the bulk of the Protestant population, were forcibly expelled.

[48] From 1712 to 1820 a succession of men held the title Chief Rabbi of Silesia ("Landesrabbiner"): Naphtali ha-Kohen (1712–16); Samuel ben Naphtali (1716–22); Ḥayyim Jonah Te'omim (1722–1727); Baruch b. Reuben Gomperz (1733–54); Joseph Jonas Fränkel (1754–93); Jeremiah Löw Berliner (1793–99); Lewin Saul Fränkel (1800–7); Aaron Karfunkel (1807–16); and Abraham ben Gedaliah Tiktin (1816–20).

[49] After the German invasion of Poland in 1939, following Nazi racial policy, the Jewish population of Silesia was subjected to Nazi genocide with executions performed by Einsatzgruppe z. B.V. led by Udo von Woyrsch and Einsatzgruppe I led by Bruno Streckenbach,[50][51] imprisonment in ghettos and ethnic cleansing to the General Government.

In their efforts to exterminate the Jews through murder and ethnic cleansing Nazi established in Silesia province the Auschwitz and Gross-Rosen camps.

After the war Silesia became a major centre for repatriation of the Jewish population in Poland which survived Nazi German extermination[56] and in autumn 1945, 15,000 Jews were in Lower Silesia, mostly Polish Jews returned from territories now belonging to Soviet Union,[57] rising in 1946 to seventy thousand[58] as Jewish survivors from other regions in Poland were relocated.

[59] The majority of Germans fled or were expelled from the present-day Polish and Czech parts of Silesia during and after World War II.

[60] Today, most German Silesians and their descendants live in the territory of the Federal Republic of Germany, many of them in the Ruhr area working as miners, like their ancestors in Silesia.