Isabel was born at Amesbury Priory, Wiltshire, on 21 March 1317, the only child of the marriage of Theobald de Verdun, 2nd Baron Verdun, Justiciar of Ireland and Lady Elizabeth de Clare. She was born eight months after her father died of typhoid on 27 July 1316. He and Elizabeth had been engaged before she was called back to England by Edward II, intent on marrying her to one of his own supporters. So Theobald abducted Elizabeth from Bristol Castle in early 1316, and married her shortly afterwards on 4 February. Elizabeth was his second wife, his first wife having been Maud Mortimer. Isabel had three half-sisters from her father's prior marriage, Joan de Verdun, Elizabeth de Verdun, and Margery de Verdun. Isabel, along with her three de Verdon half-sisters, was a co-heiress of her father. She is occasionally referred to as Heiress of Ludlow. Theobald was Elizabeth's second husband, her first husband John de Burgh had died in a minor skirmish in Galway, Ireland on 18 June 1313. She had a son by de Burgh, William Donn de Burgh, 3rd Earl of Ulster, who was Isabel's uterine half-brother. William would later marry Maud of Lancaster, by whom he had a daughter Elizabeth de Burgh, suo jure 4th Countess of Ulster. Following the death of her brother Gilbert at Bannockburn in 1314, Elizabeth, along with her two sisters, Margaret and Eleanor, became one of the greatest heiresses in England. Her uncle, King Edward II of England, ordered her to return to England, where he planned to select a husband for her from among his supporters. She was placed in Bristol Castle where Verdun would afterwards abduct her, to the fury of King Edward. After her husband's death, Elizabeth, pregnant with Verdun's child, fled to Amesbury Priory and placed herself under the protection of her aunt, Mary de Burgh, who was one of the nuns. It was there that she gave birth to Isabel. Isabel's birth is recorded in an entry of King Edward II's Wardrobe Accounts, as well as the King's gift of a silver-gilt cup which valued at one pound, ten shillings. Her paternal grandparents were Theobald de Verdun, 1st Lord Verdun and Margery de Bohun, and her maternal grandparents were Gilbert de Clare, 6th Earl of Hertford, 3rd Earl of Gloucester, and Joan of Acre, the daughter of King Edward I of England and Eleanor of Castile.
On 3 May 1317, when Isabel was just about six weeks old, her mother married Sir Roger D'Amory, Lord D'Amory, Baron of Armoy a favourite of King Edward II, who encouraged the match. Isabel's wardship and marriage rights were awarded to her stepfather. From her mother's marriage to D'Amory, Isabel had a uterine half-sister, Elizabeth D'Amory,, who would later marry Sir John Bardolf, by whom she had issue. Following D'Amory's participation in the Earl of Lancaster's rebellion of 1322, against his former friend and patron, the King and the latter's new favourites, the Despensers, Isabel's wardship and marriage rights were forfeit to the Crown and eventually passed to Queen Isabella. Isabel's aunt Eleanor de Clare was married to Hugh le Despenser the Younger, who had angered her stepfather after seizing the larger portion of the vast de Clare inheritance for himself. On account of Despenser's greed and increasing influence over the king, D'Amory joined forces with Roger Mortimer and the other disgruntled Marcher Lords becoming one of the key figures in the resulting Despenser War. Roger D'Amory died on 14 March 1322, two days before the Battle of Boroughbridge where Lancaster and the rebels were defeated by the Royalist forces. Isabel, not quite five years old, together with her sister Elizabeth and her mother, was imprisoned at Barking Abbey.
Marriage
Isabel married Henry Ferrers, 2nd Baron Ferrers of Groby in 1328 at Newbold Verdon, Leicestershire. He was the son of William Ferrers, 1st Baron Ferrers of Groby and Ellen de Seagrove. She was eleven years old at the time of her marriage. The marriage produced at least five children, four of whom survived infancy. Following the birth of her eldest child in February 1331, when Isabel was not quite 14 years of age, her mother sent her presents for her "churching". This was a special religious ceremony performed for the benefit of a woman shortly after childbirth. The child, whose sex was not recorded, died in early infancy.
Issue
Infant, whose name and sex is not known, died shortly after birth.