Princess Magdalena Reuss of Köstritz
Princess Magdalena Reuss of Köstritz (20 August 1920 - 10 October 2009) was the wife of Prince Hubertus of Prussia.
She was a member of the House of Reuss.
Prince Heinrich VIII Reuss of Köstritz
Prince Heinrich VIII Reuss of Köstritz( born 30 August 1944) is a son of Prince Heinrich I Reuss of Köstritz, and is a member of the House of Reuss.
Heinrich VII, Prince Reuss of Köstritz
Heinrich VII, Prince Reuss of Köstritz( 14 July 1825, Klipphausen – 2 May 1906, Trzebiechów) was a German diplomat.
Prince Heinrich XXXII Reuss of Köstritz
Prince Heinrich XXXII Reuss of Köstritz (4 March 1878 – 6 May 1935) was the eldest surviving son of Prince Heinrich VII Reuss of Köstritz and his wife, Princess Marie Alexandrine of Saxe-Weimar-Eisenach.
As Wilhelmina of the Netherlands was childless for the first eight years of her marriage, Heinrich XXXII was third-in-line to the Dutch throne, after the claims of his cousin William Ernest, Grand Duke of Saxe-Weimar-Eisenach and Princess Marie Alexandrine, who was Wilhelmina's cousin, William Ernest's aunt and Heinrich's mother.
William Ernest had made it clear however that he would not give up his title of Grand Duke of Saxe-Weimar-Eisenach if that was a requirement for becoming king of the Netherlands.
Furthermore, Marie Alexandrine was elderly and prone to sickness.
Thus it was assumed that she would give up her claim in favor of her eldest son, Heinrich XXXII.
Consequently, Heinrich was for all intents and purposes the heir presumptive to the Dutch throne until the birth of the future Queen Juliana in 1909.
Princess Marie Alexandrine of Saxe-Weimar-Eisenach
Princess Marie Alexandrine of Saxe-Weimar-Eisenach ("Marie Alexandrine Anne Sophie Auguste Helene";
20 January 1849 – 6 May 1922) was the eldest daughter and second child of Charles Alexander, Grand Duke of Saxe-Weimar-Eisenach and his wife Princess Sophie of the Netherlands.
Through her mother, Marie was second-in-line to the Dutch throne after her nephew William Ernest, Grand Duke of Saxe-Weimar-Eisenach from 1900 to the birth of Princess Juliana in 1909.
As her nephew was expected to abdicate his right to the throne in favor of retaining his title, Marie was expected to directly inherit the Dutch Crown upon the possible death of her still childless cousin Wilhelmina.
The birth of Juliana subsequently changed the succession.
Princess Victoria Margaret of Prussia
Princess Victoria Margaret Elizabeth Marie Ulrike of Prussia (17 April 1890 – 9 September 1923) was a member of the House of Hohenzollern.
She was the eldest daughter of Prince Friedrich Leopold of Prussia and his wife Princess Louise Sophie of Schleswig-Holstein-Sonderburg-Augustenburg.
She married Prince Heinrich XXXIII Reuss of Köstritz and had two children.
Prince Heinrich XXIV Reuss of Köstritz
Prince Heinrich XXIV Reuss of Köstritz, also" Prince Heinrich XXIV Reuss, Younger Line"( German: Heinrich XXIV.
Prinz
Reuß zu Köstritz, also" Heinrich XXIV. Prinz Reuß jüngere Linie", December 8, 1855 in Trebschen – October 2, 1910 in Ernstbrunn, Austria) was a German composer.
Prince Heinrich I Reuss of Köstritz
Prince Heinrich I Reuss of Köstritz( 8 October 191010 March 1982) was son of Prince Heinrich XXXIV Reuss of Köstritz and member of the House of Reuss.
Prince Heinrich XXXIII Reuss of Köstritz
Prince Heinrich XXXIII Reuss of Köstritz (26 July 1879 – 15 November 1942) was the son of Prince Heinrich VII Reuss of Köstritz and his wife Princess Marie Alexandrine of Saxe-Weimar-Eisenach.
Heinrich LXIII, Prince Reuss of Köstritz
Prince Heinrich LXIII Reuss of Köstritz( 18 June 1786, Berlin – 27 September 1841, Stonsdorf) was a member of the House of Reuss.

Question: Who is Prince Heinrich Xxxiii Reuss Of Köstritz's maternal grandfather?
Answer: Charles Alexander, Grand Duke of Saxe-Weimar-Eisenach