Nest (who also [in addition to Gerald fitz Walter] had by Stephen, Constable of Cardigan, a son (Robert fitz Stephen) and by Henry I another son (Henry, killed 1158, father of Meiler fitz Henry), daughter of Rhys ap Tudor Mawr, Prince of South Wales. [Burke's Peerage, p. 1679]
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He [Gerald de Windsor] married Nest, daughter of Rhys ap Tudor Mawr, PRINCE OF SOUTH WALES (e). The date of his death is not known, presumably before 1136. [Complete Peerage X:10-11, (transcribed by Dave Utzinger)]
(e) In 1106, when Owen ap Cadugan carried her off, two of her sons and a daughter by Gerald de Windsor were taken with her, the sons being returned later to their father. By Stephen, constable of Cardigan (query after Gerald's death), Nest bore a son, Robert FitzStephen, and by Henry I a son Henry (killed 1158), father of Meiler FitzHenry, which Robert and Meiler were later brothers-in-arms of the Geraldines in Ireland.