Polish communist in the context of Social Democracy of the Kingdom of Poland and Lithuania

Bolesław Bierut ([bɔˈlɛswaf ˈbʲɛrut] ; 18 April 1892 – 12 March 1956) was a Polish communist activist and politician, leader of communist-ruled Poland from 1948 until 1956. He was President of the State National Council from 1944 to 1947, President of Poland from 1947 to 1952, General Secretary of the Central Committee of the Polish United Workers' Party from 1948 to 1956, and Prime Minister of Poland from 1952 to 1954. Bierut is believed to have worked as an NKVD informant or agent prior to 1945, although his relationship with the Soviet agency has been a subject of debate among historians. As communist leader, he implemented aspects of the Stalinist system in Poland. Together with Władysław Gomułka, his main rival, Bierut is chiefly responsible for the historic changes that Poland underwent in the aftermath of World War II. Unlike any of his communist successors, Bierut led Poland until his death.

Born in Congress Poland on the outskirts of Lublin, Bierut joined the Polish Socialist Party in 1912. Later he became a member of the Communist Party of Poland and spent some years in the Soviet Union. He was sentenced to a prison term in 1935 for conducting illegal labor activity in Poland by the anti-communist Sanation government and was later released in 1938. During World War II, Bierut was an activist of the newly founded Polish Workers' Party (PPR) and subsequently the chairman of the State National Council (KRN), established by the PPR. Trusted by Joseph Stalin, Bierut participated in the Potsdam Conference, where he successfully lobbied for the establishment of Poland's western border at the Oder–Neisse line.

The 20th Congress of the Communist Party of the Soviet Union (Russian: XX съезд Коммунистической партии Советского Союза, romanized: XX syezd Kommunisticheskoy partii Sovetskogo Soyuza) was held during the period 14–25 February 1956. It is known especially for First Secretary Nikita Khrushchev's "Secret Speech", which denounced the personality cult and dictatorship of Joseph Stalin.

Delegates at this Congress of the Communist Party of the Soviet Union were given no warning of what to expect. Indeed, proceedings were opened by First Secretary Khruschev's call for all to stand in memory of the Communist leaders who had died since the previous Congress, in which he mentioned Stalin in the same breath as Klement Gottwald. Hints of a new direction only came out gradually over the next ten days, which left those present highly perplexed. The Polish communist leader Bolesław Bierut died in Moscow shortly after attending the 20th Congress.