From about at least 1343 to her death some time before February 1349, Isabel of Lancaster was Prioress of Amesbury. She was the sister of Henry of Grosmont, 1st Duke of Lancaster, a great-grandson of Henry III. She was also younger sister of the formidable Maud of Lancaster, Countess of Ulster. In 1347, the twice-widowed Maud also entered a nunnery, in her case Campsey Priory, a house of Augustinian canonesses near Wickham Market in Suffolk, but in 1364 she transferred to the Poor Clares community at Bruisyard Abbey, also in Suffolk, where she died and was buried in 1377.