Geoffrey Fitzpeter, 1st Earl of Essex (d. 1213) was a prominent part of the government of England during the reign of Richard I and John.
The patronymic is sometimes rendered Fitzpiers.
He was from a modest landowning family that had a tradition of service in mid-ranking posts under Henry II. Geoffrey's elder brother Simon was at various times sheriff of Northamptonshire, Buckinghamshire, and Bedfordshire. Geoffrey, too, got his start in this way, as sheriff of Northamptonshire for the last five years of Henry II's reign.
Around this time Geoffrey married Beatrice de Say, daughter and eventual co-heiress of William de Say. He was the son of William de Say, 3rd Baron de Say, and Beatrice, sister of Geoffrey de Mandeville, 1st Earl of Essex. This connection with the Mandeville family was to prove unexpectedly important.
In 1184 Geoffrey's father-in-law died, and he received a share of the de Say inheritance.
When Richard I left on crusade, he appointed Geoffrey one of the five judges of the king's court, and thus a principal advisor to bishop Hugh of Durham, who was chief justiciar was one of the regents during the king's absence. Later that year, Geoffrey's wife's cousin William de Mandeville, 3rd Earl of Essex died, leaving no direct heirs. His inheritance was disputed between Geoffrey and his in-laws, and Geoffrey used his political influence to eventually obtain it for himself.
On July 11, 1198 king Richard appointed Geoffrey Chief Justiciar, which at that time effectively made him the king's principal minister. He continued in this capacity after the accession of king John. On his coronation day the new king also recognized Geoffrey as Earl of Essex.
By his first wife, Beatrice de Say (described above), he had 4 children (note that his sons by this marriage took the de Mandeville surname):
Geoffrey later married Aveline, daughter of Roger de Clare, Earl of Hertford, by whom he had 3 children:
Geoffrey's first two sons died without issue. Apparently the earldom was associated with their mother's Mandeville heritage, for the earldom was inherited by the husband of their sister instead of their half-brother.