Roger de Mortimer (before 1153-before 8 July 1214) was a medieval marcher lord, residing at Wigmore Castle in the English county of Herefordshire. He was the son of Hugh de Mortimer (d. 26 February 1181) and Matilda Le Meschin.
Roger would appear to have been of age in 1174 when he fought for King Henry II against the rebellion of his son, Henry. In 1179 Roger was instrumental in the killing of Cadwallon ap Madog, the prince of Maelienydd and Elfael, both of which Mortimer coveted. He was imprisoned until June 1182 at Winchester for this killing.
The following is from Find A Grave:
Roger Mortimer, eldest surviving son and heir of Hugh and Maud. In his father's lifetime he appears on the Pipe Roll as holding terrae datae in Worcestershire and Salop. He was a benefactor of Gloucester Abbey, of Kington, St. Michael, Wilts, of Cwmhir, of Jumièges, and Saint-Victor-en-Caux. Between 1182 and 1189 he attested at Rouen a charter of Henry II to the monks of Barbey (diocese of Bayeux). In 1191, upon a charge of conspiring with the Welsh against the King, he was forced to surrender his castles and to leave the country for three years. In April 1194 he was in England again, and witnessed a charter of Richard I, after his second Coronation at Winchester. In 1210 some of his knights served in the King's invasion of Ireland.
Roger married Isabel, daughter of Walkelin de Ferrières, seigneur of Ferrières-Saint-Hilaire and lord of Oakham. Roger died before 19 August 1214, having, with the King's permission, resigned his lands to his son Hugh when he was taken ill, and was at buried at Wigmore. His widow Isabel married, 2ndly, Piers Fitz Herbert, of Blaen Llyfni, who died 1 June 1235. She retained her father's English lands till her death. She died before 29 April 1252, and was buried in the chapel, which she had built in the court of the Hospital of St. John of Lechlade.
Roger and Isabel are also the parents of Ralph and Isabel.