The House of Glücksburg (Danish: Huset Glücksborg; German: Haus Glücksburg; Greek: Οίκος του Γκλύξμπουργκ, Íkos tou Glíksbourg) (shortened version of the House of Schleswig-Holstein-Sonderburg-Glücksburg; Danish: Slesvig-Holsten-Sønderborg-Lyksborg, also spelled -Glücksborg) is a Dano-German ducal family and a branch of the House of Oldenburg, members of which have at various times reigned in Denmark, Norway and Greece. Margrethe II of Denmark, Harald V of Norway, Constantine II of Greece and Charles, Prince of Wales are patrilineal members of cadet branches of the Glücksburg dynasty.