Short answers, pulled from the story.
The Byelorussian Soviet Socialist Republic (BSSR) was a communist state founded in 1920 that became one of the four founding members of the Soviet Union in December 1922. It existed as a constituent republic of the USSR until 1991, when it declared independence and was renamed the Republic of Belarus. Minsk was its capital throughout its existence.
Over two million people were killed in Belarus during the three years of German occupation, amounting to almost a quarter of the region's population. Around 800,000 Belarusian Jews, approximately 90 percent of the Jewish population, were killed during the Holocaust. At least 5,295 settlements were destroyed and their inhabitants killed or expelled.
The BSSR was granted a separate seat in the United Nations General Assembly when the UN was founded on the 24th of October 1945, making it one of only two Soviet republics with independent UN membership alongside Ukraine. This was part of a deal with the United States to provide a degree of balance in the General Assembly, effectively giving the Soviet Union additional votes in that body.
The BSSR declared political and economic independence on the 25th of August 1991 following the failed coup in Moscow. The republic was renamed the Republic of Belarus on the 19th of September 1991. On the 8th of December 1991 Belarus signed the Belovezha Accords, which formally replaced the Soviet Union with the Commonwealth of Independent States.
In the referendum held on the 17th of March 1991, nearly 84 percent of the population voted in favor of preserving the USSR. Despite this result, Belarus declared independence just five months later on the 25th of August 1991 following the failed coup attempt in Moscow.
The BSSR initially maintained four official languages: Belarusian, Russian, Yiddish, and Polish. By the later Soviet period the official languages were Belarusian and Russian. The four-language policy reflected the Bolshevik strategy of appealing to minority populations, even though Russians and Poles together made up only about 2 percent of the republic's total population in the 1920s.