Prince Alexander of Prussia
Prince Friedrich Wilhelm Ludwig" Alexander" of Prussia( 21 June 1820 – 4 January 1896) was the eldest child of Prince Frederick of Prussia and his wife, Princess Luise of Anhalt- Bernburg.
Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg (21 April 1887 – 15 April 1957) was a daughter of Friedrich Ferdinand, Duke of Schleswig-Holstein and his wife Princess Karoline Mathilde of Schleswig-Holstein-Sonderburg-Augustenburg.
Prince Augustus of Prussia
Prince Friedrich Wilhelm Heinrich August of Prussia( 19 September 1779- 19 July 1843), known in English as Prince Augustus, was a Prussian general.
Born on Friedrichsfelde Palace, he was the youngest son of Prince Augustus Ferdinand of Prussia, the brother of King Frederick the Great, and Margravine Elisabeth Louise of Brandenburg- Schwedt.
Princess Elisabeth of Prussia
Princess Elisabeth of Prussia( 18 June 1815 – 21 March 1885) was the second daughter of Prince Wilhelm of Prussia and Landgravine Marie Anna of Hesse- Homburg and a granddaughter of Frederick William II of Prussia.
Prince Philip, Duke of Edinburgh is her great- great- grandson.
Princess Calixta of Lippe
Princess "Calixta" Agnes Adelaide Irmgard Helene Caroline Elise Emma of Lippe (14 October 1895 - 15 December 1982) was the wife of Prince Waldemar of Prussia, eldest son of Prince Henry of Prussia.
Princess Marie of Prussia (1855–1888)
Princess Marie of Prussia(" Marie Elisabeth Louise Frederika"; 14 September 1855, Marmorpalais, Potsdam – 20 June 1888, Dresden), was a princess of the House of Hohenzollern.
She was the daughter of Prince Frederick Charles of Prussia and later became second wife of Prince Henry of the Netherlands then the first wife of Prince Albert of Saxe- Altenburg.
She was also the great- niece of Wilhelm I, German Emperor.
Alexander Ferdinand, 3rd Prince of Thurn and Taxis
Alexander Ferdinand, 3rd Prince of Thurn and Taxis, full German name:" Alexander Ferdinand Fürst von Thurn und Taxis"( 21 March 1704 – 17 March 1773) was the third Prince of Thurn and Taxis, Postmaster General of the Imperial Reichspost, and Head of the Princely House of Thurn and Taxis from 8 November 1739 until his death on 17 March 1773.
Alexander Ferdinand served as Principal Commissioner at the Perpetual Imperial Diet in Frankfurt am Main and Regensburg for Charles VII, Holy Roman Emperor, Francis I, Holy Roman Emperor, and Joseph II, Holy Roman Emperor from 1 February 1743 to 1745 and again from 1748 until 1773.
Prince Alexander Ferdinand of Prussia
Prince Alexander of Prussia (Alexander Ferdinand Albrecht Achilles Wilhelm Joseph Viktor Karl Feodor; 26 December 1912 – 12 June 1985) was the only son of Prince August Wilhelm of Prussia and his wife Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg.
Princess Charlotte of Prussia (1831–1855)
Princess Charlotte of Prussia( 21 June 1831 – 30 March 1855), was by birth a Princess of Prussia and member of the House of Hohenzollern and by marriage Hereditary Princess of Saxe- Meiningen.
She was the eldest child and daughter of Prince Albert of Prussia( younger son of Frederick William III of Prussia and Louise of Mecklenburg- Strelitz) and his first wife Princess Marianne of the Netherlands( daughter of William I of the Netherlands and Wilhelmine of Prussia).
Princess Marianne of Prussia
Princess Marianne of Prussia( 23 August 19131 March 1983) was a member of the House of Hohenzollern, daughter of Prince Friedrich Wilhelm of Prussia.

Question: Who is the maternal grandfather of Prince Alexander Ferdinand Of Prussia?