Born 1899, died 1972. King of Denmark 1947-1972. Son of King Christian X of Denmark and Queen Alexandrine of Denmark. Father of Queen Margrethe II of Denmark. Husband of Queen Ingrid of Denmark.
While still crown prince, Frederik took up a career in the Danish Royal Navy and distinguished himself as a naval officer, advancing steadily in the ranks. He remained a devoted navy man throughout his life and reign, and many of his navy shipmates were lifelong friends.
After his father, King Christian X of Denmark, had become infirm as the result of a fall from his horse in October 1942 (during the German occupation of Denmark during World War II), Crown Prince Frederik took on a leading rôle as Denmark's king-in-waiting. During this period, he displayed considerable political courage and democratic spirit.
Upon the death of his father in 1947, he acceded to the throne. King Frederik IX enjoyed broad public respect and affection. This popularity resulted in the alteration in 1953 of the laws of succession (with the amendment of the Constitution of Denmark). This allowed his daughter, the later Queen Margrethe II of Denmark, to become his heir, instead of his unsuitable brother, Prince Knud.
King Frederik IX was a popular man of the people, and the down-to-earth style of his reign removed much of the mystique that had surrounded the Danish monarchy.