Leopold III (1901-1983), succeeded his father, Albert I, to the Belgian throne in 1934. A strong-willed monarch, born in Brussels, he married Princess Astrid of Sweden (1905-1935) in 1926.
An advocate of a more independent foreign policy for Belgium before World War II, Leopold twice urged mediation of the conflict between Nazi Germany and the Western Allies in the months immediately before and after the outbreak of war in 1939.
During World War II, when the German army invaded Belgium and France, Leopold, with the bulk of the Belgian army, was surrounded by the Germans and quickly capitulated. His surrender incurred the violent disapproval of the Belgian people and brought accusations of treason. Leopold, however, refused to administer his country under German control and was imprisoned first in his castle at Brussels and later in Germany. Despite his defiance of the Germans, the Belgian government-in-exile in London refused to recognize his right to rule.
After the Allied invasion in June 1944, Leopold was taken to Germany. He was liberated by American troops in Austria in May 1945. Much bitter opposition to his return existed in Belgium because of his wartime conduct. After the liberation of Belgium in 1944, the legislature elected Leopold's brother Prince Charles (1903-1983) as regent. Leopold later went into exile in Switzerland.
In 1946 a commission of inquiry exonerated Leopold of treason, but the controversy concerning his loyalty continued. When finally the Catholic People's party obtained a majority in his favour in a referendum in 1950, he went home. He met such fierce hostility, however, manifested in strikes and other protests, that he abdicated on 16 July 1951, in favour of his son Baudouin.