When she was a child, Isabel was imprisoned in Barking Abbey, along with her mother and half-sister, after her stepfather had joined the Earl of Lancaster's ill-fated rebellion against King Edward II.
William would later marry Maud of Lancaster, by whom he had a daughter Elizabeth de Burgh, suo jure 4th Countess of Ulster (6 July 1332- 10 December 1363).
Theobald abducted Elizabeth from Bristol Castle in early 1316, and married her shortly afterwards on 4 February,[3] to the fury of King Edward.
After her husband Theobold'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.
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.
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.
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".