Leopold III of Belgium

Leopold became King of the Belgians on 23 February 1934. When Germany invaded in May 1940, he surrendered his country over the objections of Prime Minister Hubert Pierlot, who fled to London and declared the act unconstitutional. The Germans placed Leopold and his family under house arrest until 1944, when they were moved to Germany, then Austria, and finally liberated by the Americans. His first wife, Astrid of Sweden, had died in a road accident in Switzerland in August 1935 - Leopold was driving when the car hit a tree. In captivity in 1941, he married Lilian Baels in a morganatic union that violated Belgian law by holding the religious ceremony before the civil one; when Lilian became pregnant, they formalized it civilly on 6 December 1941, though she was never permitted the title of queen. Banned from Belgium for years, his brother Prince Charles served as regent. Leopold's return in 1950 nearly sparked civil war and secessionist calls in Wallonia. Under pressure, he abdicated in favour of his son Baudouin on 16 July 1951.