Isabel was apparently the granddaughter and co-heiress of Ralph Fitz William, of Brompton Ralph and Withycombe, Somerset, by his wife Yolande de Mohun. 1 A number of secondary sources show Isabel's parents as Ralph Fitz William and Yolanda Fitz William, and Yolanda as daughter of the said Ralph Fitz William and Yolande de Mohun. However, none of the secondary sources consulted quote or indicate the primary source(s) in which Isabel's parents' names are shown. For the time being, therefore, Isabel's pedigree has not been included here.
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7 Feb 1270, Westminster
Inspeximus and confirmation of a charter, whereby William de Valencia, lord of Penbroch, gave to Sir Nicholas son of Martin, and Isabel his wife, for their services, 50 marks of rent, to be received by the said Nicholas and Isabel and the heirs of their bodies or their assigns, from the lands sometime of Sir Peter son of Matthew and his heirs, wherein the said Peter was formerly bound by charter to Aaron son of Abraham, a Jew of London, and which the said William had of the gift of the king, in con- sideration of £480 which the said Nicholas and Isabel gave to the said William beforehand ; the said rent to be held by rendering yearly to the said William and his heirs a red rose at Midsummer at Eclestoke, co. Wilts, if the said William shall send for it ; witnesses, Sir Richard de Middelton, chancellor of the king, and William de Wintreshul then steward of the king.
Calendar of the Charter Rolls, 54 Hen. III, m. 12
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19 Jul 1277
Accord at London between Nicholas son of Martin and Isabel his wife on the one part and Edward dean of Wells for the advowson of Westlideford. 2
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