||This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (August 2010)|
|Father||Geoffrey Fitz Peter, 1st Earl of Essex|
|Mother||Aveline de Clare|
|Died||23 November 1258|
He was not entitled to succeed his half-brother as Earl of Essex in 1227, the Earldom having devolved from his father's first wife. He was the second husband of Isabel Bigod, daughter of Hugh Bigod, 3rd Earl of Norfolk and his wife Maud Marshal of Pembroke. They had six children, one being Maud who married William de Beauchamp, 9th Earl of Warwick.
Note: The males took the FitzJohn surname ("fitz" mean "son of").
- John FitzJohn of Shere (?–1275). Married Margary, daughter of Philip Basset of Wycombe (?–1271).
- Richard FitzJohn of Shere (?–1297). Lord FitzJohn 1290. Married as her first husband, Emma (?-1332).
- Maud FitzJohn (? – 16/18 April 1301). Married firstly to Gerard de Furnivalle, Lord of Hallamshire (?–1261). Married secondly to William de Beauchamp, 9th Earl of Warwick, son of William de Beauchamp of Elmley, Worcestershire and his wife Isabel Mauduit. Had issue.
- Isabel. Married Robert de Vespont, Lord of Westmoreland (?–1264). Had issue.
- Aveline (1229–1274). Married Walter de Burgh, Earl of Ulster (1230–1271). Had issue, including Richard Og de Burgh, 2nd Earl of Ulster who in turn married Margaret de Burgh, by whom he had ten children.
- Joan (? – 4 April 1303). Married Theobald le Botiller. Had issue, from whom descend the Butler Earls of Ormond.
- O'Mahony, Charles (1912). The Viceroys of Ireland. p. 22.