A member of the Catholic Party, Pierlot became Prime Minister in 1939, shortly before Belgium entered World War II.

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.

After the liberation of Belgium in September 1944, Pierlot returned to Brussels where, against his wishes, he headed a fresh government of national unity until February 1945.

He retired from politics in 1946 amid the crisis of the Royal Question, surrounding whether Leopold could return to the Belgian throne, and died peacefully in 1963.

During the interwar period, Belgium pursued a policy of political neutrality and attempted to avoid confrontation with Nazi Germany.

When the Phoney War broke out, Pierlot became the leader of a tripartite national government of Catholics, Liberals and Socialists which stayed in power until the German invasion in May 1940.

On 24 May, as the government was leaving the country for exile in France, a group of ministers including Pierlot held a final meeting with Leopold at the Kasteel van Wijnendale.

[15] He also believed that, as a neutral power with no formal treaty of alliance with France or Britain, the Belgian army was not obliged to hold out as long as it possibly could if it incurred huge casualties and had no chance of defending its own territory.

[19] The Belgian government met in Paris on 26 May and invoked Article 82 of the Constitution, declaring the monarch unable to reign (dans l'impossibilité de régner), and resolved to continue the fight against Germany.

[21] Following the meeting, Pierlot gave a radio speech denouncing the King whom he accused of acting unconstitutionally and in sympathy with the Germans.

[23] The government met in Limoges and then withdrew to Poitiers and Bordeaux, but as the French military situation deteriorated, became split over what should happen.

De Vleeschauwer travelled to neutral Spain where, at Le Perthus on the French-Spanish border, he met with Pierlot and Paul-Henri Spaak, the Minister of Foreign Affairs, to attempt to persuade them to join him in London.

On 18 October, they escaped from confinement and headed for Portugal where the regime of António de Oliveira Salazar, although neutral, was more sympathetic to the Allied cause than Spain.

[30] Shortly after his arrived in London, during the middle of the Blitz, Pierlot narrowly avoided being killed when the Carlton Hotel, where he was staying, was destroyed in bombing in November 1940.

[33] It was also involved in coordinating the war effort of the Belgian Congo which was an important source of raw materials, like uranium, to the Allies.

[34] From early in the war, the government was able to make contact with Leopold, through various intermediaries, but was unable to create a full reconciliation between the royal and Pierlot factions.

[17] On 28 April 1941, Pierlot's two eldest children were travelling to their boarding school when the train they were on caught fire near Westborough, Lincolnshire.

[5] Pierlot was one of the chief supporters of the Benelux Customs Union negotiated with both the Dutch and Luxembourgish governments in exile and signed in September 1944.

In October 1942, Pierlot dismissed Rolin who he accused of involving himself in factional internal politics of the army, parts of which had begun to behave mutinously about their perceived inaction.

[39] The plan called for the formation of two brigades of infantry, six battalions of fusiliers, logistics and support units in Belgium immediately after liberation in order to fight alongside Allied troops during an invasion of Germany.

I must confess that this produced no reaction at all, neither hostility nor enthusiasm, just total indifference" Parliament met for the first time since 1940 on 19 September 1944 in which Pierlot presented a summary of the government's actions in Britain during the occupation.

[44] During this period, the government was involved in launching Gutt's monetary reform plan as well as the disarming of the resistance as part of the transition to stability.

A major crisis emerged within the government over the refusal of the Front de l'Indépendance (FI-OF) and the Partisans Armés (PA), two large left-wing resistance groups, to disband and disarm.

[42] Amid fears of a Communist coup d'état, parliament voted through emergency powers allowing the Gendarmerie to forcibly disarm the resistance though sporadic strikes continued.

[50] After the fall of his government, Pierlot returned to his position as senator of the arrondissements of Arlon, Marche-en-Famenne, Bastogne, Neufchâteau and Virton until the elections of February 1946.

[51] In September 1945, Pierlot was appointed to the honorary role of Minister of State by Charles and, shortly after the 1946 election, was awarded the title of Count.