PIERS DE MONTFORT, son and heir. In 1260 he was staying beyond the seas. In April 1264, he was captured at Northampton and imprisoned for a short time in Windsor Castle with his father and brother Robert. In June he had custody of Rockingham Castle for a few days; and it was probably he, and not his father, who was forbidden to take part in a tournament at Dunstable in February 1264/5. He fought at Evesham for Simon de Montfort, 4 August, and was wounded and taken prisoner. Having "appeased the King's indignation and rancour of mind," he was on 28 June 1267 pardoned for all trespasses at the time of the disturbance in the kingdom, and he recovered part of his father's lands. In 1268 he gave the advowson of Ponteland, Northumberland, which his father had bought, to his friend Walter de Merton for his newly founded college at Oxford; and in this year a grant of Ð50 per annum was renewed to him. In February 1271/2 he had protection for going on a pilgrimage to Santiago, and he went again in January 1274/5. In Nov. 1276 he was one of the magnates at a Council at Westminster concerned with Llewelyn and Welsh affairs, and in February following was going to Wales in the King's service. He was going beyond the seas in January 1277/8, and again in 1281. He gave the manor of Greetham to the Bishop of Durham for a hospital for the sick and poor. In 1280 he granted to Queen Eleanor the marriage of his eldest son John. A market and fair at Uppingham were granted to him in June 1281. In April 1282 he was summoned to serve in person against the Welsh.
He married, circa 1260, Maud, daughter and heir of Matthew, son of Henry DE LA MARE, with whom he had Ashtead in Surrey. He died before 4 March 1286/7. [Complete Peerage IX:127, (transcribed by Dave Utzinger)]
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Peter de Montfort participated in his father's treasons and was taken prisoner at the battle of Evesham, but being allowed the benefit of the Dictum of Kenilworth, he was restored to his paternal inheritance -- and afterwards enjoyed the favour of King Edward I, in whose Welsh wars he took a very active part. He d. in 1287, leaving a dau. Elizabeth (who m. 1st, William, son and heir of Simon de Montacute, and 2ndly, Sir Thomas de Furnival), and a son and heir, John de Montfort, who was the next year summoned to parliament as a baron. [Sir Bernard Burke, Dormant, Abeyant, Forfeited and Extinct Peerages, Burke's Peerage Ltd, London, England, 1883, p. 377, Montfort, Barons Montfort]