Marisco, Geoffrey de (a. 1170–1245), magnate and justiciar of Ireland, was third son of Robert de Marisco; his mother was a sister of John Cumin (qv), archbishop of Dublin. He first appears in Irish records in 1192 when his uncle granted him lands formerly held by his brother Walter. He received further grants of land in Limerick from King John (qv) (1200) and by 1215 had married Eva de Bermingham, widow of Gerald fitz Maurice FitzGerald (qv) (d. 1204), and held her lands in Offaly during his lifetime. He sided with William Marshal (qv), earl of Pembroke (d. 1219), and Walter de Lacy (qv) against the justiciar Meiler fitz Henry (qv), whom he defeated and captured at Thurles in 1208. He was pardoned by the king in 1210 and later in the year led an expedition into Connacht with Thomas fitz Maurice.
By 1215, when he was appointed justiciar, he was perhaps the most prominent magnate in Ireland, holding his own lands in Munster and Leinster and his wife's lands in Offaly, as the de Lacys and Marshal were in England. In addition, as justiciar he held the lands of Theobald Walter (qv) (d. 1205), a connection he augmented when he married his daughter Joan to Walter's heir, Theobald Butler (qv) (d. 1230). During his period in office he attempted to expand the bounds of the lordship by building a castle at Killaloe and forcing the diocese to accept his kinsman Robert Travers as the bishop. His justiciarship was also marked by corruption and misuse of funds. In 1217 he was reminded that rents and fines were to be received only at the exchequer. He ignored a summons to account for himself before the king (1218), and was summoned again in 1220. He agreed to stringent conditions for his office, including the need to account for the revenues of Ireland, and to abide by the advice of Henry of London (qv), archbishop of Dublin, who replaced him as justiciar in July 1221. In 1224 he joined with the justiciar, William Marshal (qv), earl of Pembroke (d. 1231), against Hugh de Lacy (qv), and in the following year supported Áed O'Connor, king of Connacht, against his kinsman Toirrdelbach. He was reappointed justiciar in June 1226 when Marshall's policy of supporting Áed O'Connor was reversed by the de Burghs. He was granted a salary of £580, the first salary paid to a justiciar. The change in policy was resisted by Marshal and his major tenants, including Marisco's son-in-law, Theobald Butler, and the justiciar wrote to the king recommending that their castles be confiscated. He surrendered the justiciarship of his own free will in February 1228. In 1230 he joined with the justiciar, Richard de Burgh (qv), and Walter de Lacy in an expedition to Connacht. He supported Richard Marshal, earl of Pembroke (qv), when he came to Ireland in 1234. There is no evidence to support the claim put forth by English chroniclers that he betrayed Marshal at the Curragh in April 1234, and that he was imprisoned and fined after the battle.
In 1236 his son William was outlawed for the murder of Henry Clement, a messenger from the justiciar, and Geoffrey was suspected of complicity. In 1238, when William was implicated in an attempted assassination of the king, Geoffrey suffered by association and his lands were confiscated. He fled to Scotland, where he was protected by Alexander II and Walter Comyn till 1244, when a treaty between England and Scotland forced him to leave and go to France, where he died the following year. He was married three times. The identity of his first wife, the mother of his sons Geoffrey and William and his daughter Joan, is unknown. He then married (c.1212) Eva de Bermingham (d. 1226), with whom he had several children; and finally married Alice, sister of Hugh de Lacy (d. 1242), earl of Ulster, and widow of Roger Pipard.