Amice de Clare
Amice de Clare( c. 1220 – 1284) was the daughter of Gilbert de Clare, 4th Earl of Hertford and Isabel Marshal.
She married, firstly, Baldwin de Redvers, 6th Earl of Devon, and secondly Robert de.
She founded Buckland Abbey.
Margaret de Clare
Margaret de Clare, Countess of Gloucester, Countess of Cornwall( 12 October 1293 – 9 April 1342) was an English noblewoman, heiress, and the second- eldest of the three daughters of Gilbert de Clare, 6th Earl of Hertford and his wife Joan of Acre, making her a granddaughter of King Edward I of England.
Her two husbands were Piers Gaveston and Hugh de Audley, 1st Earl of Gloucester.
Richard de Clare, 6th Earl of Gloucester
Richard de Clare, 5th Earl of Hertford, 6th Earl of Gloucester, 2nd Lord of Glamorgan, 8th Lord of Clare( 4 August 1222 – 14 July 1262) was son of Gilbert de Clare, 4th Earl of Hertford and Isabel Marshal.
He was also a powerful Marcher Lord in Wales and inherited the Lordship of Glamorgan upon the death of his father.
He played a prominent role in the constitutional crisis of 1258 – 1263.
Isabella of Gloucester and Hertford
Isabella de Clare( 2 November 1226 – 10 July 1264) was the daughter of Gilbert de Clare, 4th Earl of Hertford and 5th Earl of Gloucester and Isabel Marshal.
She is also known as" Isabel de Clare", but this is however, the name of many women in her family.
Bogo de Clare
Bogo de Clare (21 July 1248 – October 1294) was a member of the Anglo-Norman de Clare family, as third son of Richard de Clare (1222–1262), 5th Earl of Hertford and 6th Earl of Gloucester.
Elizabeth de Clare
Elizabeth de Clare, 11th Lady of Clare( 16 September 1295 – 4 November 1360) was the heiress to the lordships of Clare, Suffolk, in England and Usk in Wales.
She was the youngest of the three daughters of Gilbert de Clare, 6th Earl of Hertford and Joan of Acre, and sister of Gilbert de Clare, who later succeeded as the 7th Earl.
She is often referred to as Elizabeth de Burgh, due to her first marriage to John de Burgh.
Her two successive husbands were Theobald II de Verdun( of the Butler family) and Roger d'Amory.
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.
Joan of Acre
Joan of Acre (April 1272 – 23 April 1307) was an English princess, a daughter of King Edward I of England and Queen Eleanor of Castile.
The name "Acre" derives from her birthplace in the Holy Land while her parents were on a crusade.
She was married twice; her first husband was Gilbert de Clare, 7th Earl of Gloucester, one of the most powerful nobles in her father's kingdom; her second husband was Ralph de Monthermer, a squire in her household whom she married in secret.
Joan is most notable for the claim that miracles have allegedly taken place at her grave, and for the multiple references to her in literature.
Eleanor de Clare
Eleanor de Clare, suo jure 6th Lady of Glamorgan( 3 October 1292- 30 June 1337) was a powerful English noblewoman who married Hugh Despenser the Younger and was a granddaughter of Edward I of England.
With her sisters, Elizabeth de Clare and Margaret de Clare, she inherited her father's estates after the death of her brother, Gilbert de Clare, 8th Earl of Gloucester, 7th Earl of Hereford at the Battle of Bannockburn in 1314.
She was born in 1292 at Caerphilly Castle in Glamorgan, Wales and was the eldest daughter of Gilbert de Clare, 6th Earl of Hertford, 7th Earl of Gloucester, 5th Lord of Glamorgan and Princess Joan of Acre.
Gilbert de Clare, 8th Earl of Gloucester
Gilbert de Clare, 8th Earl of Gloucester, 7th Earl of Hertford (c. 10 May 1291 – 24 June 1314) was an English nobleman and military commander in the Scottish Wars.
In contrast to most English earls at the time, his main focus lay in the pursuit of war rather than in domestic political strife.
He was the son of Gilbert de Clare, 7th Earl of Gloucester, and Joan of Acre, daughter of King Edward I.
The older Gilbert died when his son was only four years old, and the younger Gilbert was invested with his earldoms at the young age of sixteen.
Almost immediately, he became involved in the defence of the northern border, but later he was drawn into the struggles between Edward II and some of his barons.
He was one of the Lords Ordainers who ordered the expulsion of the king's favourite Piers Gaveston in 1311.
When Gaveston was killed on his return in 1312, Gloucester helped negotiate a settlement between the perpetrators and the king.
Now one of Edward's strongest supporters, he accompanied the king on a campaign to Scotland in 1314, when several other nobles refused.
He was killed at the Battle of Bannockburn on 24 June, under somewhat unclear circumstances.
Gloucester was the most prominent of the casualties of the battle, which ended in a humiliating defeat for England.
As he had no issue, his death marked the end of the prominent de Clare family.
His estates were divided between his three sisters, one of whom was married to the king's new favourite, Hugh Despenser the younger.
Despenser's ruthless expansion of the de Clare lordship of Glamorgan in Wales led directly to the troubles of Edward II's later reign, including a rebellion in the Welsh Marches, the defeat of the Earl of Lancaster at the Battle of Boroughbridge, and eventually the deposition of the king by Roger Mortimer and Queen Isabella in 1326.

Question: Who is Gilbert De Clare, 8Th Earl Of Gloucester's maternal grandmother?