Weis" "Ancestral Roots. . ." (50:24), (53:24), (66:24), (83:24), (84:24), (88:24), (89:24), (93:24), (140:24), (141:24), (151:25), (215:24). Schwennicke (ed.) Europaische Stammtafeln, iii, 699. She was the widow of ROBERT DE BEAUMONT, count of Meulan and Earl of Leicester. It is commonly stated that before the count's death she eloped with WILLIAM DE WARENNE, whom she later married. However, see the following note.
Cokayne's "Complete Peerage" (Leicester, p.526 and notes b and d). Henry of Huntingdon states that she eloped with a certain earl during ROBERT's lifetime, which may refer to some scandal, but the whole trend of the letter does not inspire confidence in the facts stated therein.

http://www.reach.net/~roanne/beaumont.html
Isabel (Elizabeth) de Vermandois de Cpri; de Crepi, Elizabeth (Isabel) of Valois, Bretagne, France, of Vermandois.
Isabelle's mother, Alix, Countess of Vermandois & Valois, certainly belonged to an illegitimate branch of the Carolingians, but Alix' marriage to Hugues "le Grand" of France, (causa uxoris) Count of Vermandois, makes all of her descendants, including Isabelle, a member of a junior branch of the royal Capetian dynasty of France.