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.
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 Irina Nikolaïevna Orlova
Princess Irina Nikolaïevna Orlova (March 1, 1918–September 16, 1989) was the eldest child of Prince Nicholas Vladimirovich Orlov and his wife, Princess Nadejda Petrovna of Russia.
Her mother was among the Romanovs who escaped the Russian Revolution in 1919 aboard the British ship , aboard which Princess Irina was the youngest passenger.
She had one sister named Princess Xenia (aka Ksenija)
Nikolaïevna Orlova (1921–1963).
Irina Orlova Nikolaievna married Baron Hans von Waldstatten (1918–1977) in Rome 27 March 1940.
They divorced in 1946.
They had one daughter:
After her divorce, Irina had a son named Alexis Nicolas Orlov.
He was born 10 September 1947.
She married Anthony Adama Zylstra (1902–1982) in the Hague, the Netherlands on 8 January 1960.
She died on 16 September 1989 at age 71 at Villacerf, France.
Irina Yusupova
Princess Irina Felixovna Yusupova, nicknamed" Bébé",( 21 March 1915 – 30 August 1983) was born in Petrograd, Russian Empire, the only child of Prince Felix Yusupov and Princess Irina of Russia.
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.
Princess Nadejda Petrovna of Russia
Princess Nadejda Petrovna of Russia (Russian: Надежда Петровна; 3 March 1898 – 21 April 1988) was the third child of Grand Duke Peter Nikolaevich of Russia and his wife, the former Princess Milica of Montenegro.
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.
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.
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.

Question: Who is Princess Irina Nikolaïevna Orlova's maternal grandmother?
Answer: Princess Milica of Montenegro