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.
Despina Khatun
Theodora Megale Komnene , also known as Despina Khatun (from the Greek title "Despoina" and Mongol title "Khatun", both meaning "Lady, princess, queen"), was the daughter of John IV of Trebizond, who married the Aq Qoyunlu ruler Uzun Hasan in 1458.
She became the mother of Martha (Halima) who became the mother of first Safavid king, Shah Ismail I.
Some older writers refer to her as "Catherine".
Charles Diehl has shown that it was based on DuCange's misunderstanding of the Mongol title "Khatun" as "Catherine".
John IV agreed to the marriage only if his daughter was allowed to continue her Orthodox Christian religion, a condition which Uzun Hasan agreed upon.
Despina was famous for her extreme beauty amongst the Greek women.
She was accompanied by a group of Orthodox Christian priests and was allowed to build Orthodox churches in Iran.
Uzun Hasan strengthened his anti-Ottoman alliance by this marriage and gained the support of many Greek, Armenian and Georgians.
Marriage between Christians and Muslim rulers, although uncommon, was not unprecedented.
Speros Vryonis provides several examples from the Sultanate of the Seljuk Turks, beginning with Kilij Arslan II.
A later example is Michael VIII Palaiologos marrying off his illegitimate daughters Euphrosyne and Maria to Nogai Khan and Abaqa Khan respectively.
Previous Emperors of Trebizond had married off his female relatives, most notably Alexios III, during whose reign two of his sisters and two of his daughters were married to rulers of neighboring Muslim states.
In Western Europe, Theodora inspired the myth of the "Princess of Trebizond", a fixture of tales of damsels in distress as well as of a possible grand Crusade against the Ottoman Turks.
The legend inspired several artists, including Pisanello and Jacques Offenbach.
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.
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.
John IV of Trebizond
John IV Megas Komnenos
(΄ Μέγας Κομνηνός, "Iōannēs IV Megas Komnēnos") (1403 – c.1459) was Emperor of Trebizond from 1429 until his death.
He was a son of Emperor Alexios IV of Trebizond and Theodora Kantakouzene.
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.
Hüma Hatun
Hüma Hatun (1410 ‒ September 1449) was the fourth wife of Ottoman Sultan Murad II and mother of Mehmed II and the grandmother of Bayezid II.
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.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
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 the paternal grandmother of Despina Khatun?
Answer: Theodora Kantakouzene