" William was an illegitimate son of Henry II, King of England. His mother was unknown for many years until the discovery of a charter William made that mentions "Comitissa Ida, mater mea" (Countess Ida, my mother).[2][3] This referred to Ida de Tosny, a member of the prominent Tosny (or Toesny) family, who had married Roger Bigod, 2nd Earl of Norfolk[4] in 1181.

" Ida Longespée, married firstly Ralph who was son of Ralph de Somery, Baron of Dudley, and Margaret, daughter of John Marshal;[13] she married secondly William de Beauchamp, Baron of Bedford, by whom she had seven children.

This Ida is sometimes confused with Ida II Longespée, who married Sir Walter FitzRobert of Woodham Walter, Essex, by whom she had issue including Ela FitzWalter, wife of William de Odyngsells. Ida II Longespée has been given different parents by different genealogists; G. Andrews Moriarty suggested the two Idas were sisters; Gerald Paget suggests Ida II who married Walter FitzRobert may have been the daughter of William Longespée II, Earl of Salisbury, by his wife, Idoine de Camville. "

Children of William de Beauchamp and Ida Longespee were: Maud de Beauchamp b abt 1234, d bef Apr 1273.
She md Roger de Mowbray abt 1247, son of William de Mowbray and Avice. Ela de Beauchamp b abt 1240, Essex, England, d 1266.
She md Baldwin Wake abt 1254, son of Hugh Wake and Joan de Stuteville.
Beatrice de Beauchamp b abt 1245, prob Bedford, Bedfordshire, England, d 1280-1281.
She md Sir Thomas Fitz Otho bef 1264.
Their daughter, Maud/Matilda Fitz Thomas md Sir John de Botetourte abt 1284.

Ida de Tosny, Countess of Norfolk (died after 1181), was a Norman royal mistress. Named after her grandmother Ida de Hainaut, she was the daughter of Ralph IV de Tosny (died 1162) and his wife Margaret (born c. 1125 and living in 1185), a daughter of Robert de Beaumont, 2nd Earl of Leicester.[1]

Relationship to King Henry II Ida de Tosny was a royal ward and mistress of Henry II, King of England, by whom she was mother of one of his illegitimate sons, William Longespée, 3rd Earl of Salisbury,[2] (c. 1176 – 7 March 1226), as demonstrated by the discovery of a charter of William mentioning "Comitissa Ida, mater mea" (Countess Ida, my mother).[3] Ida was not the first English royal ward to be taken as a royal mistress. Isabel de Beaumont (Elizabeth de Beaumont), was the ward of King Henry I and the mistress of one of his sons.