Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Ralph Neville, 3rd Earl of Westmorland
Ralph Neville, 3rd Earl of Westmorland( c. 1456 – 6 February 1499) was an English peer.
He was the grandfather of Ralph Neville, 4th Earl of Westmorland.
Isabella of France
Isabella of France (1295 – 22 August 1358), sometimes described as the She-Wolf of France , was Queen of England as the wife of Edward II, and regent of England from 1327 until 1330.
She was the youngest surviving child and only surviving daughter of Philip IV of France and Joan I of Navarre.
Isabella was notable in her lifetime for her diplomatic skills, intelligence, and beauty.
She became a "femme fatale" figure in plays and literature over the years, usually portrayed as a beautiful but cruel and manipulative figure.
Isabella arrived in England at the age of 12 during a period of growing conflict between the king and the powerful baronial factions.
Her new husband was notorious for the patronage he lavished on his favourite, Piers Gaveston, but the queen supported Edward during these early years, forming a working relationship with Piers and using her relationship with the French monarchy to bolster her own authority and power.
After the death of Gaveston at the hands of the barons in 1312, however, Edward later turned to a new favourite, Hugh Despenser the Younger, and attempted to take revenge on the barons, resulting in the Despenser War and a period of internal repression across England.
Isabella could not tolerate Hugh Despenser and by 1325 her marriage to Edward was at a breaking point.
Travelling to France on a diplomatic mission, Isabella may have begun an affair with Roger Mortimer, and the two may possibly have agreed at this point to depose Edward and oust the Despenser family.
The Queen returned to England with a small mercenary army in 1326, moving rapidly across England.
The King's forces deserted him.
Isabella deposed Edward, becoming regent on behalf of her son, Edward III.
Some believe that Isabella then arranged the murder of Edward II.
Isabella and Mortimer's regime began to crumble, partly because of her lavish spending, but also because the Queen successfully, but unpopularly, resolved long-running problems such as the wars with Scotland.
In 1330, Isabella's son Edward III deposed Mortimer in turn, taking back his authority and executing Mortimer.
The Queen was not punished, however, and lived for many years in considerable style—although not at Edward III's court, though she often visited to dote on her grandchildren and was marginally involved in peace talks—until her death in 1358.
John of Eltham, Earl of Cornwall
John of Eltham, 1st Earl of Cornwall (15 August 1316 – 13 September 1336) was the second son of Edward II of England and Isabella of France.
He was heir presumptive to the English throne until the birth of his nephew Edward, the Black Prince.
John of Cornwall (theologian)
John of Cornwall, in Latin Johannes Cornubiensis or Johannes de Sancto Germano was a Christian scholar and teacher, who was living in Paris about 1176.
He is not to be confused with the fourteenth- century John of Cornwall who expounded Latin at his grammar school in English instead of French.
There was also an archdeacon of Worcester called John of Cornwall around 1197, who probably was a different person.
John of Cornwall (grammarian)
John of Cornwall, possibly called in Latin Johannes Cornubiensis or Johannes de Sancto Germano was a 14th- century scholar and teacher, author of the English grammar" Speculum Grammaticale"
He is not to be confused with the twelfth- century theologian John of Cornwall who authored the" Eulogium ad Alexandrum Papam III".
There was also a Benedictine monk John of St. Germans who wrote a" Commentarius in Aristotelis libros duo analyticorum posteriorum"( now at the Magdalen College, Oxford); it is not clear whether these were the same person.
It has been claimed as one of the great ironies of history that three Cornish- speaking Cornishmen brought the English language back from the verge of extinction- John of Cornwall, John Trevisa and Richard Pencrych.
John Christian Kunkel
John Christian Kunkel (September 18, 1816 – October 14, 1870) was a Whig and Republican member of the U.S. House of Representatives from Pennsylvania.
He was the grandfather of John Crain Kunkel.
Isabel Marshal
Isabel Marshal (9 October 1200 – 17 January 1240) was a medieval English countess.
She was the wife of both Gilbert de Clare, 4th Earl of Hertford and 5th Earl of Gloucester and Richard, 1st Earl of Cornwall (son of King John of England).
With the former, she was a great grandmother of King Robert the Bruce of Scotland.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Gilbert Talbot, 3rd Baron Talbot
Gilbert Talbot, 3rd Baron Talbot( c. 1332–1387) was an English nobleman and soldier.
He was the grandfather of John Talbot, 1st Earl of Shrewsbury.

Question: Who is the maternal grandfather of John Of Eltham, Earl Of Cornwall?
Answer: Philip IV of France