Tage Erland von Gerber (born 8 February 1885 in Sölvesborg, died 9 June 1966) was a Swedish landowner, captain and genealogist.
 He was the founder of Ointroducerad Adels Förening, the Association of the Unintroduced Nobility of Sweden, in 1911, and the editor of Sveriges ointroducerade adels kalender, the second almanach of unintroduced nobility in Sweden to be published, from 1912 to 1944.
 He was owner of Falla Manor in Östergötland.
 In 1960, he was named honorary member of Ointroducerad Adels Förening, the second person to be so honoured after Prince Carl Bernadotte.
Gullan Marianne Bernadotte, Countess of Wisborg (née "Lindberg"; 15 July 1924), also known as "Princess Marianne Bernadotte", is a Swedish actress and philanthropist who in 1961 married Sigvard Bernadotte, the second son of King Gustaf VI Adolf.
 Since the death of Gunnila Bernadotte in 2016, she (by marriage) is the last to survive of the aunts and uncles of King Carl XVI Gustaf of Sweden.
Prince Bernadotte was a title in the nobility of Luxembourg, conferred upon Oscar Bernadotte by Adolphe of Luxembourg in 1892, and in the nobility of Belgium, conferred upon Carl Bernadotte by Leopold III of Belgium in 1937.
 It was also used earlier by the founder of their royal House of Bernadotte.
Princess Kristine Bernadotte, born Kristine Rivelsrud, (22 April 1932 – 4 November 2014) was a Norwegian-born princess of Belgian nobility.
 She was the third wife and widow of Prince Carl Bernadotte, a former royal prince of Sweden, to whom she was married from 1978 until his death in 2003.
Princess Ingeborg of Denmark ("Ingeborg Charlotte Caroline Frederikke Louise"; 2 August 1878 – 12 March 1958), was a Princess of Sweden by marriage to Prince Carl, Duke of Västergötland.
 She was the daughter of Frederick VIII of Denmark, and the maternal grandmother of Harald V of Norway, Baudouin and Albert II of Belgium, and the female line great grandmother of Henri of Luxembourg.
The Blank family is a family of Jews, some of whom converted to Orthodox Christianity in the Russian Empire, mostly notable as the immediate ancestry of the maternal grandfather of Vladimir Lenin according to various published researchers who suggest that Lenin's maternal grandfather was a Jewish convert to Christianity (Alexander Blank).
 Whether or not Lenin, whose matrilineal "Blank" surname also traces to non-Jewish German roots, was actually partly descended from the Jewish Blank family remains contested.
Baron O'Hagan, of Tullahogue in the County of Tyrone, is a title in the Peerage of the United Kingdom.
 It was created on 14 June 1870 for Sir Thomas O'Hagan, then Lord Chancellor of Ireland.
 His younger son, the third Baron, served as a Lord-in-Waiting (government whip in the House of Lords) from 1907 to 1910 in the Liberal administrations of Sir Henry Campbell-Bannerman and H. H. Asquith and was later a Deputy Speaker of the House of Lords.
 In 1909 Lord O'Hagan assumed by Royal licence the additional surname of Towneley, which was that of his maternal grandfather.
 s of 2010 the title is held by his grandson, the fourth Baron, who succeeded in 1961.
 He is the son of the Hon. Thomas Anthony Edward Towneley Strachey (d. 1955).
 Lord O'Hagan was a Member of the European Parliament for Devon from 1973 to 1975 and again from 1979 to 1994, first as an independent and later as a Conservative.
 He assumed in 1938 by deed poll the additional Christian name of Towneley and the surname of Strachey in lieu of his patronymic.
 Strachey was the surname of his maternal grandfather Edward Strachey, 1st Baron Strachie.
Prince Carl Philip of Sweden, Duke of Värmland (] ; Carl Philip Edmund Bertil; born 13 May 1979) is the only son and the second of three children of King Carl XVI Gustaf and Queen Silvia.
 s of 2016 , Prince Carl Philip is fourth in the line of succession, after his older sister, Crown Princess Victoria, his niece and goddaughter Princess Estelle, and his nephew Prince Oscar.
 He lives with his wife, Princess Sofia, and two sons, Prince Alexander and Prince Gabriel, in Villa Solbacken in central Stockholm.
Carl Gustaf Oscar Fredrik Christian, Prince Bernadotte (10 January 1911 – 27 June 2003), originally Prince Carl, Duke of Östergötland, was the youngest child and only son of Prince Carl of Sweden and Princess Ingeborg of Denmark and eventually a prince of the Belgian nobility.
 To distinguish himself from his father, he was widely known as "Carl Junior."
 He was the brother of Princess Margaretha of Sweden, Queen Astrid of Belgium and Crown Princess Märtha of Norway.
Princess Margaretha of Sweden (Margaretha Sofia Lovisa Ingeborg; 25 June 1899 – 4 January 1977) was a member of the Swedish Royal Family and a Princess of Denmark by marriage, the eldest sister of Märtha, Crown Princess of Norway, Queen Astrid of the Belgians and Prince Carl Bernadotte.

Question: Who was the maternal grandfather of Prince Carl Bernadotte?
Answer: Frederick VIII of Denmark