King Leopold III and Prince Baudouin awaiting the verdict of the Belgium people. King Leopold III (3 November 1901 - 25 September 1983) was King of the Belgians from 1934 until 1951. On the outbreak of World War II, Leopold tried to maintain Belgian neutrality, but after the German invasion in May 1940, he surrendered his country, earning him much hostility, both at home and abroad. Prince Baudouin (7 September 1930 - 31 July 1993), Dutch name Boudewijn, was King of the Belgians from 1951 until his death in 1993. He was the last Belgian king to be sovereign of the Congo.