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.
Thomas de Clare, Lord of Thomond
Thomas de Clare, 1st Lord of Thomond, 1st Lord of Inchiquin and Youghal (1244×124729 August 1287) was a Hiberno-Norman peer and soldier.
He was the second son of Richard de Clare, 6th Earl of Gloucester and his wife Maud de Lacy, Countess of Gloucester.
In 1272 he served a term as Lieutenant of the Duchy of Aquitaine.
On 26 January 1276 he was granted the Lordship of Thomond by Edward I of England; he spent the next eight years attempting to conquer it from the O'Brien dynasty, kings of Thomond.
Richard de Clare, Steward of Forest of Essex
Richard de Clare (after 1281 – 10 May 1318)
1st
Lord Clare was the son of Thomas de Clare, Lord of Thomond and Juliana FitzGerald.
A descendant of Strongbow, he succeeded his older brother, Gilbert, in 1308 as Lord of Thomond.
In 1309, and then again between 1312 and 1316, he was sheriff of Cork.
Forced to put down a number of rebellions, he was eventually killed while commanding his forces at the Battle of Dysert O'Dea near what is now Ennis, County Clare.
According to legend, the day before his death, Richard de Clare beheld a woman dressed in white on the river's edge washing bloody clothing and armor.
When he asked whose clothes they were, she replied, "yours," and then vanished.
This woman was believed to be a banshee foretelling his death the next day when he lay dead with his clothes caked in blood on the battlefield of Dysert O'Dea
(Lewis Spence, The Magical Arts in Celtic Britain 81(1999)).
Richard was succeeded by his son Thomas, who was born in 1318 and died three years later.
A series of inquisitions post mortem that were held following a writ issued on 10 April 1321 established that Thomas' heirs were his father's sisters; Margaret, the wife of Bartholomew de Badlesmere and Maud, the wife of Sir Robert de Welle.
As well as stewardship of the Forest of Essex, Thomas' estate included numerous properties in Ireland.
Richard de Clare, 3rd Earl of Hertford
Richard de Clare, 3rd Earl of Hertford, lord of Clare, Tonbridge, and Cardigan( – 1217), was a powerful Norman nobleman with vast lands in England and Wales.
Rohese de Clare
Rohese de Clare( bef. 1166) was a member of the wealthy and powerful de Clare family and a strong patron of Monmouth Priory.
Richard de Luci
Richard de Luci( 1089 – 14 July 1179)( also Richard de Lucy) was first noted as High Sheriff of Essex, after which he was made Chief Justiciar of England.
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.
Maud de Lacy, Countess of Hertford and Gloucester
Maud de Lacy,( 25 January 1223 – 10 March 1289), was an English noblewoman, being the eldest child of John de Lacy, 2nd Earl of Lincoln, and the wife of Richard de Clare, 5th Earl of Hertford, 6th Earl of Gloucester.
Gilbert de Clare, 5th Earl of Gloucester
Gilbert de Clare, 4th Earl of Hertford, 5th Earl of Gloucester, 1st Lord of Glamorgan, 7th Lord of Clare( 1180 – 25 October 1230) was the son of Richard de Clare, 3rd Earl of Hertford( c. 1153 – 1217), from whom he inherited the Clare estates.
He also inherited from his mother, Amice Fitz William, the estates of Gloucester and the honour of St. Hilary, and from Rohese, an ancestor, the moiety of the Giffard estates.
In June 1202, he was entrusted with the lands of Harfleur and Montrevillers.

Question: Who is the paternal grandfather of Richard De Clare, Steward Of Forest Of Essex?
Answer: Richard de Clare, 6th Earl of Gloucester