Maurice de Berkeley
Sir Maurice de Berkeley" the Resolute"( 1218- 4 April 1281), 5th( feudal) Baron de Berkeley, was an English soldier and rebel, residing at Berkeley Castle in the English county of Gloucestershire.
Norborne Berkeley, 4th Baron Botetourt
Norborne Berkeley, 4th Baron Botetourt( c. 1717 – 15 October 1770), was a British courtier, member of parliament, and royal governor of the colony of Virginia from 1768 until his death in 1770.
Maurice de Berkeley, 4th Baron Berkeley
Maurice de Berkeley, 4th Baron Berkeley (c. 1330 – 8 June 1368), "The Valiant", feudal baron of Berkeley, of Berkeley Castle in Gloucestershire, was an English peer.
His epithet, and that of each previous and subsequent head of his family, was coined by John Smyth of Nibley (died 1641), steward of the Berkeley estates, the biographer of the family and author of "Lives of the Berkeleys".
He was born in Berkeley Castle in Gloucestershire, the eldest son and heir of Thomas de Berkeley, 3rd Baron Berkeley by his wife Lady Margaret Mortimer.
In August 1338 Berkeley married Elizabeth le Despenser, daughter of Hugh Despenser the younger by his wife Eleanor de Clare.
By Elizabeth he had seven children as follows:
Henry Berkeley, 7th Baron Berkeley
Henry Berkeley, 7th Baron Berkeley( 26 November 1534 – 26 November 1613) was an English peer and politician.
He was Lord Lieutenant and Vice- Admiral of Gloucestershire.
He was the grandfather of George Berkeley, 8th Baron Berkeley.
Thomas Berkeley, 5th Baron Berkeley
Thomas Berkeley, "de jure" 5th Baron Berkeley, (b. 1472 - 22 January 1532) was a British soldier and aristocrat.
He was born to Sir Maurice Berkeley, "de jure" 3rd Baron Berkeley, and Isabel Meade, in England.
He was the younger brother to Maurice Berkeley, "de jure" 4th Baron Berkeley, and had a younger brother, James, and younger sister, Anne.
On 9 September 1513 he fought in the Battle of Flodden and was knighted by the Earl of Surrey, Thomas Howard.
He later became Constable of Berkeley Castle on 15 May 1514, and Sheriff of Gloucestershire, November 1522 - November 1523.
By writ, he was succeeded to the title of "de jure" 5th Baron Berkeley on 12 September 1523 after his brother Maurice's death, and his eldest son Thomas followed as the "de jure" 6th Baron Berkeley, again by writ.
Margaret Mortimer, Baroness Berkeley
Margaret Mortimer, Baroness Berkeley (2 May 1304 – 5 May 1337) was the wife of Thomas de Berkeley, 3rd Baron Berkeley.
She was the eldest daughter of Roger Mortimer, 1st Earl of March, the "de facto" ruler of England from 1327 to 1330, and his wife Joan de Geneville, Baroness Geneville.
William Berkeley, 4th Baron Berkeley of Stratton
William Berkeley, 4th Baron Berkeley of Stratton PC, PC( I)( d. 24 March 1741), was a British politician and judge, of the Bruton branch of the Berkeley family.
He was Master of the Rolls in Ireland between 1696 and 1731 and also held political office as Chancellor of the Duchy of Lancaster from 1710 to 1714 and as First Lord of Trade from 1714 to 1715.
Margaret Beaufort, Countess of Stafford
Margaret Beaufort( 1437 – 1474) was a daughter of Edmund Beaufort, 2nd Duke of Somerset and Lady Eleanor Beauchamp.
Her maternal grandparents were Richard de Beauchamp, 13th Earl of Warwick and his first wife Elizabeth Beauchamp, 4th Baroness Lisle.
Elizabeth was daughter of Thomas de Berkeley, 5th Baron Berkeley and Margaret de Berkeley, 3rd Baroness Lisle, becoming the main heiress of her mother.
James Berkeley, 1st Baron Berkeley
James Berkeley, 1st Baron Berkeley( c. 1394 – 22 October 1463), also known as" James the Just", was an English peer.
Berkeley was the son of Sir James de Berkeley and his wife Elizabeth( née Bluet).
He was made heir to his uncle Thomas de Berkeley, 5th Baron Berkeley.
He was married four times.
His third wife was Lady Isabel, daughter of Thomas Mowbray, 1st Duke of Norfolk; and his fourth wife was the Lady Joan Talbot, daughter of John Talbot, 1st Earl of Shrewsbury.
Lord Berkeley was involved in a bitter feud with his cousin Elizabeth, daughter of the fifth Baron Berkeley and wife of Richard de Beauchamp, 13th Earl of Warwick.
He was unable initially to claim Berkeley Castle, as it was taken in possession by the Earl and Countess of Warwick.
In 1421, when the Warwicks finally gave up Berkeley Castle, James was summoned to Parliament by writ as Lord Berkeley.
The feud did not end there as his third wife Isabel was captured by the Countess of Warwick's son -in- law the Earl of Shrewsbury, and held imprisoned until her death in 1452.
Lord Berkeley was succeeded by his son from his third marriage, William, who was created Marquess of Berkeley in 1489.
Eleanor Beauchamp, Duchess of Somerset
Lady Eleanor Beauchamp, Baroness de Ros and Duchess of Somerset( September 1408 – 6 March 1467) at Wedgenock, Warwickshire, England, was the second daughter of Richard de Beauchamp, 13th Earl of Warwick and Elizabeth de Berkeley, daughter of Thomas de Berkeley, 5th Baron Berkeley.

Question: Who is Maurice De Berkeley, 4Th Baron Berkeley's maternal grandfather?
Answer: Roger Mortimer, 1st Earl of March