Overview
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.
Family
Born at Pembroke Castle, Isabel was the seventh child, and second daughter, of William Marshal, 1st Earl of Pembroke and Isabel de Clare. This means that she was a member of the Marshal Family. She had 9 siblings: 4 sisters and 5 brothers, who included the 2nd, 3rd, 4th, 5th and 6th Earls of Pembroke; each of her brothers dying without a legitimate male heir, thus passing the title on to the next brother in line. Her last brother to hold the title of Earl of Pembroke died without legitimate issue, and the title was passed down through the family of Isabel's younger sister Joan. Her sisters married, respectively, the Earls of Norfolk, Surrey, and Derby; the Lord of Abergavenny and the Lord of Swanscombe.
First marriage
On her 17th birthday, Isabel was married to Gilbert de Clare, 4th Earl of Hertford and 5th Earl of Gloucester, who was 20 years her senior, at Tewkesbury Abbey. The marriage was an extremely happy one, despite the age difference, and the couple had six children:
Agnes de Clare (b. 1218)
Amice de Clare (1220–1287), who married the 6th Earl of Devon
Richard de Clare, 5th Earl of Hertford (1222–1262)
Isabel de Clare (2 November 1226 – 10 July 1264), who married the Robert de Brus, 5th Lord of Annandale; through this daughter, Isabel would be the great grandmother of Robert the Bruce
William de Clare (1228–1258)
Gilbert de Clare (b. 1229), a priest
Isabel's husband Gilbert joined in an expedition to Brittany in 1229, but died 25 October 1230 on his way back to Penrose, in that duchy. His body was conveyed home by way of Plymouth and Cranborne, to Tewkesbury, where he was buried at the abbey.
From Wikipedia (CC BY-SA 4.0).