Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
John Montagu, 1st Baron Montagu
John de Montacute  was a 14th-century English nobleman and loyal servant of King Edward III.
He was the son of William Montagu, 1st Earl of Salisbury by his wife Catherine Grandison, and younger brother of William de Montacute, 2nd Earl of Salisbury (1328–1397).
He also had several younger sisters.
Montacute was summoned to parliament in 1357.
Jean Froissart named "Lord John Mountacute" as one of the participants with King Edward III at the Siege of Calais in 1349.
He married Margaret de Monthermer, daughter and heiress of Thomas de Monthermer, 2nd Baron de Monthermer by his wife Margaret de Brewes.
Their children included John Montacute, 3rd Earl of Salisbury (– 1400); Eleanor Montacute, who married John Dinham (1359–1428); Thomas Montagu, Dean of Salisbury Cathedral; and Sybil Montagu, Prioress of Amesbury.
Montagu's descendants quartered the arms of Monthermer: "Or, an eagle displayed vert beaked and membered gules".
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.
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.
Catherine Grandison, Countess of Salisbury
Catherine Grandison, Countess of Salisbury (c. 1304 – 23 November 1349) was an English noblewoman, remembered for her relationship with King Edward III of England and possibly the woman in whose honour the Order of the Garter was originated.
She was the daughter of William de Grandison, 1st Baron Grandison, and Sibylla de Tregoz.
Her mother was one of two daughters of John de Tregoz, Baron Tregoz (whose arms were blazoned "Gules two bars gemels in chief
a lion passant guardant or"), maternal granddaughter of Fulk IV, Baron FitzWarin).
Catherine married William Montacute, 1st Earl of Salisbury in about 1320.
Their children were:
According to rumour, King Edward III was so enamoured of the countess that he forced his attentions on her in around 1341, after having relieved a Scottish siege on Wark Castle, where she lived, while her husband was out of the country.
An Elizabethan play, "Edward III", deals with this incident.
In the play, the Earl of Warwick is the unnamed Countess's father, though he was not her father in real life.
In around 1348, the Order of the Garter was founded by Edward III
and it is recorded that he did so after an incident at a ball when the "Countess of Salisbury" dropped a garter and the king picked it up.
It is assumed that Froissart is referring either to Catherine or to his daughter-in-law, Joan of Kent.
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.
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.
Edward Montagu, 1st Baron Montagu
Edward Montagu( or Edward de Montacute), 1st Baron Montagu( d. 14 July 1361) was an English peer.
He fought at the Battle of Crecy.
His first wife, Alice of Norfolk, the granddaughter of Edward I, died as the result of an assault committed by Montagu and his retainers.
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.
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 John Montagu, 1St Baron Montagu's maternal grandmother?
Answer: Sibylla de Tregoz