Bolesław Bierut

As chairman of the Constitutional Committee from September 1951, Bierut presided over the drafting of a new constitution. In the fall of 1951 Stalin personally reviewed the Russian translation and inserted roughly fifty corrections across the preamble and twenty-two articles, which Bierut faithfully incorporated into the Polish text. After a nationwide 'public discussion,' the constitution was proclaimed on 22 July 1952. It renamed the state the 'Polish People's Republic' (Polska Rzeczpospolita Ludowa), abolished the presidency, and created a collective head of state: the Council of State, elected by the Sejm. The Sejm was declared the 'supreme organ of state power,' representing 'the working people of towns and villages,' yet the real locus of power, the PZPR, remained outside the constitutional text. The document, amended twenty-four times, served as Poland's fundamental law until the new Constitution of 1997.

Bierut attended the 20th Congress of the CPSU (14–25 February 1956) as a guest. Unlike the rest of the Polish delegation he did not return to Poland, remaining in Moscow hospitalised with severe influenza that developed into pneumonia and heart complications. After the congress the delegation set out for Warsaw but Bierut stayed behind, and almost no one outside a narrow circle of the leadership knew of his illness. He died in Moscow on 12 March 1956 after reading the text of Khrushchev's 'Secret Speech', aged 63 (born 18 April 1892).

The cause of death is disputed. The official medical finding, signed among others by Vladimir Vasilenko, records that he fell ill with influenza and pneumonia in late February 1956; on the night of 12 March an acute attack of cardiovascular weakness with impaired coronary circulation (myocardial infarction) occurred, and the post-mortem attributed death at 23:35 Moscow time to cardiac arrest caused by increasing thrombosis of the pulmonary artery. Polish Radio reported heart attack on 13 March; the documented hour of death varies between 21:30 (21:35 Polish time in one source) and 23:35 Moscow time. The circumstances remain unclear: hypotheses of poisoning, suicide and shooting by Politburo member and alleged Soviet agent Franciszek Mazur circulated, none confirmed, though doubt about the official cause was widespread even at PZPR meetings. The most likely real cause is his long-deteriorating health, with progressive atherosclerosis and kidney disease from at least 1955.

National mourning was declared for 13–16 March 1956. The coffin lay in state in Moscow and then Warsaw; the funeral was held on 16 March and he was buried in the Avenue of Merit at Powązki Military Cemetery. A several-hour procession ran from the Palace of Culture and Science to the cemetery, transmitted by Polish Radio for hours, and Warsaw residents were given a day off. Catholic bishops complied with the demand that church bells ring nationwide on the funeral day. The two remaining members of the ruling 'trio' alongside him, Hilary Minc and Jakub Berman, were removed; at the Sixth Plenum of the PZPR Central Committee on 20 March, with Khrushchev present, Edward Ochab was elected first secretary. Earlier, on 3 March, at a Warsaw conference of party activists, Staszewski and others sharply criticised the leadership including the absent Bierut. Imprisoned activists were also freed, among them Marian Spychalski on 6 March. According to historian Andrzej Garlicki, Bierut died 'just in time': had he lived longer, the political demise of Berman and Minc, the triumphal return of Gomułka and de-Stalinization in Poland could have been stalled. On 18 April 1956 a merchant ship built at Gdańsk Shipyard was named Bolesław Bierut.