Kaoru Hatoyama
After the elections of 2009, she became more widely known as the grandmother of Prime Minister Yukio Hatoyama and his politician brother Kunio Hatoyama.
Hubba bint Hulail
Hubba bint Hulail was the grandmother of Hashim ibn' Abd Manaf, thus the great- great- great- grandmother of the Islamic" Nabī"( Prophet) Muhammad ibn Abdullah.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
Countess Palatine Maria Anna of Zweibrücken-Birkenfeld
Countess Palatine Maria Anna of Zweibrücken-Birkenfeld-Bischweiler (18 July 1753 – 4 February 1824) was Countess Palatine of Birkenfeld-Gelnhausen and Duchess in Bavaria, through her marriage to Duke Wilhelm in Bavaria.
Maria Anna was a great-grandmother of Empress Elisabeth of Austria through his son Duke Pius August in Bavaria
Duke Siegfried August in Bavaria
Duke Siegfried in Bavaria, full German name: "
Siegfried August Maximilian Maria, Herzog in Bayern"
(10 July 1876,
Bamberg, Kingdom of Bavaria – 12 March 1952, Munich, Republik of Bavaria) was a Duke in Bavaria and member of the House of Wittelsbach.
Siegfried August was the first of three sons of Duke Maximilian Emanuel in Bavaria and his wife Princess Amalie of Saxe-Coburg and Gotha.
Siegfried August was the brother of "Christoph" Joseph Clemens Maria, Duke in Bavaria and "Luitpold" Emanuel Ludwig Maria, Duke in Bavaria.
Duchess Marie Gabrielle in Bavaria
Duchess Marie Gabrielle in Bavaria( 9 October 1878 in Tegernsee, Bavaria – 24 October 1912 in Sorrento, Italy) was the youngest daughter of Duke Karl Theodor in Bavaria and his second wife, Infanta Maria Josepha of Portugal.
She married Prince Rupprecht of Bavaria in 1900 but died before he became Crown Prince.
Through her second son Albrecht, Marie Gabrielle was the grandmother of the present Duke of Bavaria, Franz.
Duke Franz Joseph in Bavaria
Duke Franz Joseph in Bavaria, full German name:" Franz Joseph Michael Karl
Maria Evaristus Quirinus Ottokar Herzog in Bayern"( 23 March 1888, Schloss Tegernsee, Kingdom of Bavaria – 23 September 1912, Munich, Kingdom of Bavaria) was a Duke in Bavaria and member of the House of Wittelsbach.
Franz Joseph was the fifth and youngest child of Duke Karl- Theodor in Bavaria and his wife Infanta Maria Josepha of Portugal.
Franz Joseph was the brother of Duke Ludwig Wilhelm in Bavaria and sisters Duchess Amalie in Bavaria, Duchess Sophie Adelheid in Bavaria, Duchess Elisabeth in Bavaria and Duchess Marie Gabrielle in Bavaria.
Mona Hopton Bell
Mona Hopton Bell( 1867- 1940) was a British artist, best known for her portraits of civic figures.
She was the grandmother of the painter Jean H. Bell.
Princess Amalie of Saxe-Coburg and Gotha
Princess Amalie of Saxe-Coburg and Gotha (Marie Luise Franziska Amalie; 23 October 1848 – 6 May 1894) was a Princess of Saxe-Coburg and Gotha by birth and a Duchess in Bavaria through her marriage to Duke Maximilian Emanuel in Bavaria.
Amalie was the fourth child and second eldest daughter of Prince August of Saxe-Coburg and Gotha and his wife Princess Clémentine of Orléans.
Her youngest brother was Ferdinand I of Bulgaria.
Tjuyu
Tjuyu( sometimes transliterated as Thuya or Thuyu) was an Egyptian noblewoman and the mother of queen Tiye, and the wife of Yuya.
She is the grandmother of Akhenaten, and great grandmother of Tutankhamun.

Question: Who is Duke Siegfried August In Bavaria's maternal grandmother?
Answer: Princess Clémentine of Orléans