Dictionary of National Biography, 1885-1900/Mauduit, William
MAUDUIT, WILLIAM, Earl of Warwick (1220–1268), was son of William Mauduit of Hanslape, whose great-grandfather of the same name was chamberlain to Henry I. William Mauduit (d. 1257) fought in the barons' war against John, during which his castle of Hanslape was taken and destroyed by Fawkes de Breauté on 28 Nov. 1215. He was present on the same side at Lincoln on 20 May 1217. In 1233 he had to give his son as a hostage to the king, but was taken into favour next year. He died in April 1257, leaving by his wife Alice, daughter of Waleran, earl of Warwick, one son, William, and a daughter Isabella. William Mauduit was thirty-six years old at his father's death. On the death of John de Plessis, second husband of his cousin Margaret, countess of Warwick, Mauduit became Earl of Warwick, on 4 April 1263, in right of his mother, and in the same year was summoned to the Welsh war under that title. In the barons' war he at first sided with Simon de Montfort, but afterwards joined the king. In April 1264 he was surprised at Warwick Castle by John Giffard [q. v.], taken prisoner with his wife, and imprisoned at Kenilworth. He had to pay nineteen hundred marks for his ransom. He was hereditary chamberlain to the king. Mauduit died on 8 Jan. 1268, having married Alice, daughter of Gilbert de Segrave. He left no children, and the earldom of Warwick consequently passed to his sister's son, William Beauchamp, who was father of Guy de Beauchamp [q. v.]
[Matthew Paris; Flores Historiarum (both in Rolls Ser.); Dugdale's Baronage, i. 398–9; Doyle's Official Baronage, iii. 577.]