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.
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.
Eleanor de Bohun
Lady Eleanor de Bohun (– 3 October 1399) was the elder daughter and co-heiress with her sister, Mary de Bohun, of their father Humphrey de Bohun, 7th Earl of Hereford (1341–1373).
Her mother was Lady Joan Fitzalan, daughter of Richard FitzAlan, 10th Earl of Arundel and his second wife Eleanor of Lancaster.
Eleanor Percy, Duchess of Buckingham
Eleanor Percy, Duchess of Buckingham( – 13 February 1530), also known as Alianore, was the eldest daughter of Henry Percy, 4th Earl of Northumberland, by his wife, Lady Maud Herbert, daughter of William Herbert, 1st Earl of Pembroke.
Eleanor Percy married Edward Stafford, 3rd Duke of Buckingham, who was beheaded in 1521 on false charges of plotting to overthrow the king, Henry VIII.
As a result, the Dukedom of Buckingham and estates were forfeited, and her children lost their inheritance.
Humphrey Stafford, Earl of Stafford
Humphrey Stafford( – 1458), generally known by his courtesy title of Earl of Stafford, was the eldest son of Humphrey Stafford, 1st Duke of Buckingham and Lady Anne Neville( d. 1480).
Margaret de Stafford
Margaret Stafford( born c. 1364; died 9 June 1396) was the daughter of Hugh de Stafford, 2nd Earl of Stafford, and Philippa de Beauchamp.
She was the first wife of Ralph Neville, 1st Earl of Westmorland, and the grandmother of the 2nd Earl.
Humphrey, 2nd Earl of Buckingham
Humphrey, 2nd Earl of Buckingham (1381–1399) was an English peer and member of the House of Lords.
He was Lord High Constable of England.
His father, Thomas of Woodstock, was the youngest son of King Edward III and uncle of Richard II.
After the murder of his father, he became the ward of the crown, along with Henry of Monmouth (the future King Henry V), eldest son and heir of Henry Bolingbroke (the future King Henry IV).
Richard II took both boys with him to Ireland in 1398, where they were left in custody at Kells, when Richard returned to face Bolingbroke.
Once Richard II had been deposed, Henry Bolingbroke ordered their release and summoned them home
but Humphrey, who was sickly, died on the way on 2 September 1399.
His mother Eleanor de Bohun died shortly after, allegedly because of her sorrow after the loss of her son.
Walter Giffard, 2nd Earl of Buckingham
Walter Giffard, 2nd Earl of Buckingham( died 1164) was an English peer.
He inherited the earldom in 1102 from his father Walter Giffard, 1st Earl of Buckingham, and died without issue in 1164( during the reign of King Henry II); he was buried in Nutley, Sussex.
His estate was divided between William Marshal, Earl of Pembroke, and Richard de Clare, Earl of Hertford who were the two heirs of Rohais, his sister and daughter of the first Earl of Buckingham.
John Stafford, 1st Earl of Wiltshire
John Stafford, 1st Earl of Wiltshire,( 24 November 1427 – 8 May 1473) was an English nobleman, the youngest son of Humphrey Stafford, 1st Duke of Buckingham.
In 1461 he was appointed Knight of the Order of the Bath.
Thomas Bruce, 2nd Earl of Ailesbury
Thomas Bruce, 2nd Earl of Ailesbury( later styled Aylesbury) and 3rd Earl of Elgin( 1656 – 16 December 1741) was an English politician and memoirist.
He was the son of Robert Bruce, 2nd Earl of Elgin, and Lady Diana Grey.
His maternal grandparents were Henry Grey, 1st Earl of Stamford, and Lady Anne Cecil, daughter of William Cecil, 2nd Earl of Exeter.
His" Memoirs", which were not published until long after his death, are a valuable source for English history in the last quarter of the seventeenth century.

Question: Who is Humphrey, 2Nd Earl Of Buckingham's maternal grandfather?
Answer: Humphrey de Bohun, 7th Earl of Hereford