Diana Guardato
Diana Guardato was a member of the aristocratic Patrician Guardato family, and had three children with King Ferdinand I: Diana Guardato is the 16th- Great Grandmother of His Royal Highness Albert II of Belgium, 15th- Great Grandmother of His Majesty Juan Carlos
I of Spain, 17th- Great Grandmother of Philippe of Belgium, 14th- Great Grandmother of His Majesty Manuel II of Portugal, 16th- Great Grandmother of Grand Duke Henri, as well as many others.
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.
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.
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.
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.
Purnima (Hindi actress)
Purnima Das Verma( born Meherbhano Mohammad Ali) was an Indian film actress who worked predominantly in Hindi language films.
She is the grandmother of actor Emraan Hashmi.
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.
Lady Harriet Mary Montagu
Harriet Mary Baring, Baroness Ashburton
(née Lady Harriet Montagu)
(14 May 1805 – 4 May 1857) was a socialite and hostess.
She was born in 1805 to George Montagu, 6th Earl of Sandwich and Louisa Montagu, Countess of Sandwich.
She married William Bingham Baring, 2nd Baron Ashburton on 12 April 1823.
He had graduated from Oriel College, Oxford in 1823
and he was an M.P. by 1826.
He was the Member of Parliament for Thetford, Callington, Winchester, North Staffordshire and finally Thetford for a second time before he became a peer in 1848.
He served in Sir Robert Peel's government despite his shyness.
She was witty and direct.
The welcome that she gave at her various houses attracted leading men of her time:
William Thackeray, John Stuart Mill and especially Thomas Carlyle enjoyed her company.
She and the Earl of Sandwich were notably wealthy and they had houses in Surrey, Bath House, Piccadilly, another near Portsmouth and a place near Winchester.
The Earl was involved in government, a fellow of the Royal Society, and a trustee of the National Gallery and in 1860 he became President of the Royal Geographical Society.
She was the hostess for, and a source of friction between, Thomas Carlyle and his wife, Jane Welsh Carlyle.
Jane Carlyle was jealous of the attention that her husband gave to his hostess, but she was also one of her admirers.
As a literary hostess, she had been described as chinless, large, and with an unusual nose, but both the Carlyles recognised her intelligence.
Jane noted that despite her appearance she was "almost beautiful—simply through the intelligence and cordiality of her expression."
She died in Paris on 4 May 1857 having had only one child who died as an infant.
Her husband married Louisa Caroline Stewart-Mackenzie at Bath House in Piccadilly on 17 November 1858.
George Montagu, 6th Earl of Sandwich
George John Montagu, 6th Earl of Sandwich (4 February 1773 – 21 May 1818) was the son of John Montagu, 5th Earl of Sandwich and Lady Mary Henrietta Powlett.
He was styled Viscount Hinchingbrooke from 1790 until in 1814 when, his elder half-brother having died, he inherited the earldom from his father, together with the Hinchingbrooke estate in Huntingdonshire.
He was educated at Eton College {1780-90) and Trinity College, Cambridge (1790-92).
He was MP for Huntingdonshire from 1794 to 1814.
He married in 1804 Lady Louisa Mary Ann Julia Harriet Lowry-Corry, daughter of Armar Lowry-Corry, 1st Earl Belmore and Lady Harriet Hobart.
Together they had two daughters and one son, John William, who would succeed his father in the earldom:
He died in Rome in 1818.

Question: Who is the paternal grandmother of Lady Harriet Mary Montagu?
Answer: Lady Mary Henrietta Powlett