Frederick IX of Denmark was born 11 March 1899 Sorgenfri in Kongens Lyngby, Denmark to Christian X of Denmark (1870-1947) and Alexandrine von Mecklenburg-Schwerin (1879-1952) and died 14 January 1972 Copenhagen, Denmark of unspecified causes. He married Ingrid av Sverige (1910-2000) 24 May 1935 in Stockholm, Sweden. Johan Willem Friso van Nassau-Dietz (1687-1711), Willem van Oranje (1533-1584), Alfred the Great (849-899)/s, Charlemagne (747-814)/s, Henry II of England (1133-1189)/s, Willem van Oranje (1533-1584)/s, Hugh Capet (c940-996)/s, Gustav I of Sweden (1496-1560)/s, William I of England (1027-1087)/s, Robert I of Scotland (1274-1329)/s, Rollo of Normandy (860-932)/s.
|Margrethe II of Denmark (1940-)||16 April 1940 Copenhagen, Denmark||Henri de Laborde de Monpezat (1934-2018)|
|Benedikte of Denmark (1944-)|
|Anne-Marie of Denmark (1946-)||30 August 1946 Amalienborg Palace, Copenhagen, Denmark||Constantine II of Greece (1940-)|