The Skaggs-Files

Eleanor de Warenne was born about 1251 at Warren, Sussex, England. She was the daughter of John de Warenne, 7th Earl of Surrey and Alix de Lusignan. Eleanor de Warenne married Henry de Percy, son of William de Percy and Eleanor de Baliol, on 8 September 1268 at York, Yorkshire, England.
This marriage produced 3 sons, they were: 1. John de Percy, b. 1270, d. Bef 20 Jul 1293; 2. William de Percy, d. date unknown; 3. Henry de Percy, Lord Percy, b. 25 Mar 1273, Petworth, Sussex, England, d. Between 2 Oct 1314 and 10 Oct 1314. Eleanor died about 1282 in Craven, Yorkshire, England, and her burial place is Sawley Abbey {Sallay Abbey, Yorkshire, England}. (Bio by Audrey Hoffman)

From Douglas Richardson:
Eleanor was the daughter of John de Warrene and Alice de Lusignan, the granddaughter of William de Warenne and Maud Marshall, Hughes X de Lusignan and Isabella de Taillefer.

She was the wife of Sir Henry de Percy, the son of William de Percy, Baron of Topcliffe and his second wife, Ellen de Balliol. They married at York on 08 Sept 1268 and had three sons:
* William
* John 1270-bef 1293
* Sir Henry m Eleanor de Arundel

Sir Henry Sr died 29 August 1272, and Eleanor allegedly married the son of a Scottish Lord. She was alive in 1282.

Eleanor was born circa 1244 at Surrey, England per The Peerage and Richard Glanville-Brown, who also refers to her as Eleanor Plantagenet.

Paul McBride list her birth as 1251 in Warren, Sussex, his sources are Europaische Stammtafeln, 1938 Burke's Peerage, Turton's Plantagenet Ancestry, Frederick Lewis Weis's Ancestral Roots, and Magna Charta Pedigrees.

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"History of the House of Percy" lists her as Eleanor Plantagenet, but if you go back several paternal generations this Eleanor de Warren is descended from Hamelin Plantagenet, but Hamelin's children mostly took their mother's surname. Complete Peerage shows her as Alianore Plantagenet, but as the daughter of John de Warren.