 On 21 March 1929 in Oslo, he married his first cousin Princess Märtha of Sweden with whom he had two daughters, Ragnhild and Astrid and one son, Harald.As exiles during World War II, Crown Princess Märtha and the royal children lived in Washington, D.C., where she struck up a close friendship with Franklin D. Roosevelt.She died in 1954, before her husband ascended the throne.