Princess Helene of Waldeck and Pyrmont (1899–1948)

Princess Helene of Waldeck and Pyrmont (Helene Bathildis Charlotte Maria Friederike; 22 December 1899 – 18 February 1948) was the only daughter of Friedrich, Prince of Waldeck and Pyrmont, last reigning Prince of Waldeck and Pyrmont, and wife of Nikolaus, Hereditary Grand Duke of Oldenburg. She was named after her paternal aunt Princess Helena, Duchess of Albany (1861–1922) who married Prince Leopold, Duke of Albany, youngest son of Queen Victoria

Marriage
Helena married on 26 October 1921 in Arolsen, Nikolaus, Hereditary Grand Duke of Oldenburg (1897–1970), third child and first son of Frederick Augustus II, Grand Duke of Oldenburg and Duchess Elisabeth Alexandrine of Mecklenburg-Schwerin.

Issue

 * 1) Anton-Günther, Duke of Oldenburg (16 January 1923 – 20 September 2014) married Princess Ameli of Löwenstein-Wertheim-Freudenberg, had issue
 * 2) Duchess Rixa of Oldenburg (28 March 1924 – 1 April 1939); died unmarried and without issue
 * 3) Duke Peter of Oldenburg (7 August 1926 – 18 November 2016); married Princess Gertrude of Löwenstein-Wertheim-Freudenberg andhad issue
 * 4) Duchess Eilika of Oldenburg (2 February 1928 – 26 January 2016); married Emich, 7th Prince of Leiningen, had issue
 * 5) Duke Egilmar of Oldenburg (b. 14 October 1934)
 * 6) Duke Friedrich August of Oldenburg (11 January 1936 - 9 July 2017); married first Princess Marie Cécile of Prussia, had issue, second Donata Countess of Castell-Rüdenhausen, no issue
 * 7) Duchess Altburg of Oldenburg (b. 14 October 1938) married Baron Rüdiger of Erffa and had issue
 * 8) Duke Huno of Oldenburg (b. 3 January 1940) married Countess Felicitas-Anita of Schwerin von Krosigk and had issue.
 * 9) Duke Johann of Oldenburg (b. 3 January 1940) married Countess Ilka of Ortenburg, had issue.

Titles and styles

 * 22 December 1899 – 26 October 1921 Her Serene Highness Princess Helene of Waldeck and Pyrmont.
 * 26 October 1921 – 18 February 1948 Her Royal Highness The Hereditary Grand Duchess of Oldenburg.