See also
| Name: | William of MANDEVILLE |
| Sex: | Male |
| Father: | Geoffrey + of MANDEVILLE (1092-1144) |
| Mother: | Rohese + of VERE (1103-aft1166) |
| Birth | 1142 (est) | |
| Occupation | frm 1166 to 1189 (age 23-47) | Earl of Essex |
| Title | frm 1180 to 1189 (age 37-47) | Count of Aumala |
| Title | 1189 (age 46-47) | Chief Justicar of England |
| Death | 14 Nov 1189 (age 46-47) |
William de Mandeville, 3rd Earl of Essex (1st Creation) (died 14 November 1189) was a loyal councilor of Henry II and Richard I of England.
He was the second son of Geoffrey de Mandeville, 1st Earl of Essex and Rohese de Vere, Countess of Essex. After his father's death while in rebellion (1144), William grew up at the court of the Count of Flanders. On the death of his elder brother Geoffrey in 1166, he became Earl of Essex and returned to England, where he spent much time at the court of Henry II. He stayed loyal to the king during the Revolt of 1173–1174 known as the Revolt of the Young King.
In 1177 he became a crusader, in company with a companion of his youth, Count Philip of Flanders. Philip attempted to intervene in the court politics of the Kingdom of Jerusalem but was rebuffed, and the two fought for the Principality of Antioch at the siege of Harim. William returned to England in the fall of 1178.
In 1180 he married Hawise, daughter and heiress of William, Count of Aumale, who had died the previous year. He gained possession of her lands, both in Normandy and in England, along with the title of Count of Aumale (or Earl of Albemarle as it is sometimes called).
William fought in the wars against the French toward the end of Henry II's reign, and was at the deathbed of that king in 1189. He carried the crown at the coronation of Richard I and held the favor of the new king. Richard I appointed him one of the two chief justiciars of England.[1] But William died at Rouen a few months later on a mission to Normandy, without issue. He was buried at Mortemar Abbey in Normandy, founded by his Mandeville ancestors.[2]
He was initially succeeded by his elderly aunt, Beatrice de Say, née Mandeville, who passed her claim to her surviving son, Geoffrey de Say. Geoffrey contracted to pay an unprecedentedly large relief for the Mandeville inheritance, but he rapidly fell into arrears. Geoffrey Fitz Peter, the husband of Beatrice's granddaughter and namesake, Beatrice de Say, was a prominent man at court and used his position to push his wife's claim. She was the eldest daughter of Geoffrey de Say's elder brother. Eventually the estates and, later, the earldom, went to Geoffrey Fitz Peter by right of his wife.