Hubert Marie Eugène Pierlot was a Belgian politician and Prime Minister of Belgium, serving between 1939 and 1945. Pierlot, a lawyer and jurist, served in World War I before entering politics in the 1920s. A member of the Catholic Party, Pierlot became Prime Minister in 1939, shortly before Belgium entered World War II. In this capacity, he headed the Belgian government in exile, first from France and later Britain, while Belgium was under German occupation. During the German invasion of Belgium in May 1940, a violent disagreement broke out between Pierlot and King Leopold III over whether the King should follow the orders of his ministers and go into exile or surrender to the German Army. Pierlot considered Leopold's subsequent surrender a breach of the Constitution and encouraged the parliament to declare Leopold unfit to reign. The confrontation provoked a lasting animosity between Pierlot and other conservatives, who supported the King's position and considered the government's exile to be cowardly.

Achille Van Acker was a Belgian politician who served three terms as the prime minister of Belgium between 1946 and 1958. A moderate from Flanders, Van Acker was a member of the Belgian Socialist Party (PSB–BSP) and played an important role in the creation of the Belgian welfare state after World War II.