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.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
Anne Denman
Anne Denman( 1587–1661) was born in Olde Hall, Retford, Nottinghamshire.
Through a fortunate second marriage with Thomas Aylesbury, she became the grandmother of Lady Anne Hyde, Duchess of York and great- grandmother of Queen Mary II and Queen Anne.
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.
Gülbahar Hatun (wife of Mehmed II)
Gülbahar Hatun( 1432 – 1492) was the consort of Sultan Mehmed II, and mother of Sultan Bayezid II of the Ottoman Empire and the grandmother of Selim I.
Victoria de Marichalar y Borbón
" Doña" Victoria Federica de Todos los Santos de Marichalar y Borbón( born 9 September 2000) is the younger child and only daughter of the Spanish Infanta Elena, Duchess of Lugo, and" Don" Jaime de Marichalar.
" Doña" Victoria Federica is fifth in the line of succession to the Spanish Throne, after her brother Felipe.
Felipe de Marichalar y Borbón
"Don" Felipe Juan Froilán de Todos los Santos de Marichalar y Borbón (born 17 July 1998 in Madrid) is the elder child and only son of the Duchess of Lugo, Infanta Elena of Spain, and "Don" Jaime de Marichalar.
Felipe is fourth in the line of succession to the Spanish Throne, after his mother.
Infanta Elena, Duchess of Lugo
Infanta Elena, Duchess of Lugo
(Elena María Isabel Dominica de Silos de Borbón y de Grecia; born 20 December 1963) is the first child and elder daughter of King Juan Carlos I of Spain and Queen Sofía of Spain, and third in the line of succession to the Spanish throne.
She has a younger sister, Infanta Cristina, and a younger brother, King Felipe VI.
Infanta Elena has represented her family abroad on several occasions, having travelled to Germany, the United Kingdom, the United States, Argentina, Japan, Peru, and the Philippines.
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.
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.

Question: Who is the maternal grandmother of Felipe De Marichalar Y Borbón?
Answer: Queen Sofía of Spain