Belarusians in the context of "Territories of Poland annexed by the Soviet Union"

The Slavs or Slavic people are a major ethnic group in Europe. They speak Slavic languages and preserve Slavic culture. There are 13 Slavic countries in Europe, which include: Poland, the Czech Republic, Slovakia, Russia, Belarus, Ukraine, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, North Macedonia, and Bulgaria; the Slavs comprise a population of around 300 million people. There are three different Slavic ethnic groups: the West Slavs, the East Slavs, and the South Slavs; the Poles, Silesians, Kashubians, Sorbs, Czechs, and Slovaks are West Slavs; Russians, Belarusians, Ukrainians, and Rusyns are East Slavs; while Slovenes, Resians, Croats, Bosniaks, Serbs, Montenegrins, Torlakians, the Gorani, the Torbeši, Macedonians, and Bulgarians are South Slavs. Slavs are geographically distributed throughout the northern parts of Eurasia; they predominantly inhabit Central Europe, Eastern Europe, Southeastern Europe, and Northern Asia, though there is a large Slavic minority scattered across the Baltic states and Central Asia, and a substantial Slavic diaspora in the Americas, Western Europe, and Northern Europe.

Early Slavs lived during the Migration Period and the Early Middle Ages (approximately from the 5th to the 10th century AD), and came to control large parts of Central, Eastern, and Southeast Europe between the sixth and seventh centuries. Beginning in the 7th century, they were gradually Christianized. By the 12th century, they formed the core population of a number of medieval Christian states: East Slavs in the Kievan Rus', South Slavs in the Bulgarian Empire, the Principality of Serbia, the Duchy of Croatia and the Banate of Bosnia, and West Slavs in the Principality of Nitra, Great Moravia, the Duchy of Bohemia, and the Kingdom of Poland.

Christianity is the main religion in Belarus, with Eastern Orthodoxy being the largest denomination. The legacy of the state atheism of the Soviet era is apparent in the fact that a proportion of Belarusians (especially in the east part of the country) are not religious. Moreover, other non-traditional and new religions have sprung up in the country after the end of the Soviet Union.

The East Slavs are the most populous subgroup of the Slavs. They speak the East Slavic languages, and formed the majority of the population of the medieval state Kievan Rus', which they consider their cultural ancestor. Belarusians, Russians and Ukrainians are the existing East Slavic groups. Rusyns are sometimes considered a separate nation, though they are often considered a subgroup of Ukrainians.

Russians (Russian: русские, romanized: russkiye [ˈruskʲɪje] ) are an East Slavic ethnic group native to Eastern Europe. Their mother tongue is Russian, the most spoken Slavic language. The majority of Russians adhere to Orthodox Christianity, ever since the Middle Ages. By total numbers, they compose the largest Slavic and European nation.

Genetic studies show that Russians are closely related to Poles, Belarusians, Ukrainians, as well as Estonians, Latvians, Lithuanians, and Finns. They were formed from East Slavic tribes, and their cultural ancestry is based in Kievan Rus'. The Russian word for the Russians is derived from the people of Rus' and the territory of Rus'. Russians share many historical and cultural traits with other European peoples, and especially with other East Slavic ethnic groups, specifically Belarusians and Ukrainians.

Ruthenia is an exonym, originally used in Medieval Latin, as one of several terms for Rus'. Originally, the term Rus' land referred to a triangular area, which mainly corresponds to the tribe of Polans in Dnieper Ukraine. Ruthenia was used to refer to the East Slavic and Eastern Orthodox people of the Grand Duchy of Lithuania and the Kingdom of Poland, and later the Polish-Lithuanian Commonwealth and Austria-Hungary, mainly to Ukrainians and sometimes Belarusians, corresponding to the territories of modern Belarus, Ukraine, Eastern Poland and some of western Russia.

Historically, in a broader sense, the term was used to refer to all the territories under Kievan dominion (mostly East Slavs).

The Second Polish Republic, officially known at the time as the Republic of Poland, was a country in Central and Eastern Europe that existed between 7 October 1918 and 6 October 1939 after being established in the final stage of World War I. The Second Republic was taken over in 1939, after it was invaded by Nazi Germany, the Soviet Union, and the Slovak Republic, marking the beginning of the European theatre of the Second World War. The Polish government-in-exile was established in Paris and later London after the fall of France in 1940.

When, after several regional conflicts, most importantly the victorious Polish-Soviet war, the borders of the state were finalized in 1922, Poland's neighbours were Czechoslovakia, Germany, the Free City of Danzig, Lithuania, Latvia, Romania, and the Soviet Union. It had access to the Baltic Sea via a short strip of coastline known as the Polish Corridor on either side of the city of Gdynia. Between March and August 1939, Poland also shared a border with the then-Hungarian governorate of Subcarpathia. In 1938, the Second Republic was the sixth largest country in Europe. According to the 1921 census, the number of inhabitants was 25.7 million. By 1939, just before the outbreak of World War II, this had grown to an estimated 35.1 million. Almost a third of the population came from minority groups: 13.9% Ukrainians; 10% Ashkenazi Jews; 3.1% Belarusians; 2.3% Germans and 3.4% Czechs and Lithuanians. At the same time, a significant number of ethnic Poles lived outside the country's borders.

Lebensraum (German pronunciation: [ˈleːbənsˌʁaʊm] , lit. 'living space') is a German concept of expansionism and Völkisch nationalism, the philosophy and policies of which were common to German politics from the 1890s to the 1940s. First popularized around 1901, Lebensraum became a geopolitical goal of the German Empire in World War I (1914–1918), as the core element of the Septemberprogramm of territorial expansion. The most extreme form of this ideology was promoted and initiated by the Nazi Party, that had ruled Nazi Germany, whose ultimate goal of which was to establish a Greater German Reich. Lebensraum was a leading motivation of Nazi Germany to initiate World War II, and it would continue this policy until the end of the conflict.

Following Adolf Hitler's rise to power, Lebensraum became an ideological principle of Nazism and provided justification for the German territorial expansion into Central and Eastern Europe. The Nazi policy Generalplan Ost (lit. 'Master Plan for the East') was based on its tenets. It stipulated that Germany required a Lebensraum necessary for its survival and that most of the populations of Central and Eastern Europe would have to be removed permanently (either through mass deportation to Siberia, extermination, or enslavement), including Polish, Ukrainian, Russian, Belarusian, Czech, and other Slavic nations considered non-Aryan. The Nazi government aimed at repopulating these lands with Germanic colonists in the name of Lebensraum during and following World War II. Entire populations were ravaged by starvation; any agricultural surplus was used to feed Germany. The Jewish population was to be exterminated outright.