Prince Henry was born on 31 March 1900, at York Cottage, on the Sandringham Estate during the reign of his great-grandmother Queen Victoria. His father was the Duke of York (later King George V), the only surviving son of the Prince and Princess of Wales (later King Edward VII and Queen Alexandra).
Prince Joachim Friedrich Ernst Waldemar of Prussia (10 February 1868 – 27 March 1879) was the sixth child and youngest son of German Crown Prince Friedrich (later Emperor Friedrich III), and Victoria, Princess Royal, the eldest daughter of the British Queen Victoria
Prince Frederick Charles Alexander of Prussia (German: Friedrich Karl Alexander; 29 June 1801 – 21 January 1883) was a younger son of Frederick William III of Prussia. He served as a Prussian general for much of his adult life and became the first Herrenmeister (Grand Master) of the Order of Saint John after its restoration as a chivalric order. 
Louis Ferdinand, Prince of Prussia (German: Louis Ferdinand Victor Eduard Adalbert Michael Hubertus Prinz von Preußen; 9 November 1907 – 26 September 1994) was a member of the princely House of Hohenzollern, which occupied the Prussian and German thrones, until the abolition of those monarchies in 1918.
Otto, Prince of Bismarck, Count of Bismarck-Schönhausen, Duke of Lauenburg (German: Otto Fürst von Bismarck, Graf von Bismarck-Schönhausen, Herzog zu Lauenburg, pronounced [ˈɔtoː fɔn ˈbɪsmaʁk] (); 1 April 1815 – 30 July 1898), born Otto Eduard Leopold von Bismarck, was a conservative German statesman and diplomat.
Prince Franz Wilhelm is a grandson of Prince Joachim of Prussia, the youngest son of Emperor Wilhelm II. In 2002 Prince Franz Wilhelm with Theodor Tantzen founded the Prinz von Preußen Grundbesitz AG, a project development and project management company which restores old buildings in Germany.
He served as an officer to the Habsburgs of Austria, and in 1829, Emperor Francis I created him Prince of Vasa (German: Prinz von Wasa). During the Greek War of Independence (1821–1829) there was some talk of Gustav becoming its first king, but this never materialized.