Left fatherless, his lands were initially in the keeping of the Chief Justiciar of England,
Ranulf de Glanvill. In 1191, though under age, he paid a 1,000-mark fee to inherit his father's lands. In that year he also married a widow who was an illegitimate daughter of King
William I of Scotland. Later he inherited from his mother one-third of the Trussebut estates, which included lands near the town of
Bonneville-sur-Touques in
Normandy, of which he became hereditary
bailiff and
castellan. In 1196, during fighting between King
Richard I of England and King
Philip II of France, Richard captured a French knight worth a significant ransom and put him in the castle of Bonneville. When the keeper of the castle let the knight escape, an angry Richard had the man hanged and imprisoned Ros, fining him 1,200 marks (though he was later let off 275 marks). Like many magnates, he had an uneasy relationship with King John after 1199. He witnessed the King's charters, served in his armies, went on diplomatic missions for him (one in 1199 to Ros's father-in-law in Scotland), and on one occasion was reported gambling with him in Ireland. Tension arose in 1205, when John ordered his lands to be seized but later relented. It was possibly then that his younger son was taken as a hostage by the King. In 1206 he was given permission to mortgage his lands if during the next three years he went to Jerusalem, as a crusading knight or as an individual pilgrim. The permission was renewed in 1207, but his record was marred by the escape that year of another prisoner under his supervision, for which he was fined 300 marks. Back in favour in 1209, he was sent again on a diplomatic mission to Scotland but does not seem to have gone to Palestine, for in 1210 he was serving with John in Ireland. In 1212, on account of him entering a monastic order, John gave custody of his lands to Sir
Philip Oldcoates. But he re-entered secular life the next year, when the King made him
sheriff of Cumberland and appointed him to a commission investigating grievances in
Lincolnshire and
Yorkshire. In the latter county, he worked for a reconciliation between John and
William de Forz, heir to the extensive estates there of
Hawise, Countess of Aumale. In October 1213 he was one of the witnesses when John surrendered England to the authority of the Pope and he was one of the twelve guarantors appointed to ensure John kept his promises. Throughout the disturbances of 1214 and the first quarter of 1215 he remained loyal to John, being rewarded with royal manors in Cumberland and royal support for the election of his aunt as
abbess of
Barking Abbey. However he then joined the rebel barons as one of the 25 chosen to enforce observance of Magna Carta, being appointed by them to control Yorkshire and possibly Northumberland. For this he was
excommunicated by the Pope, and John gave his lands to William de Forz. Ordered by John to give up
Carlisle Castle, he did so but remained on the rebel side after the death of John in October 1216, supporting
Prince Louis even after his elder son was captured by the loyalist side in May 1217. He finally submitted later that year, and regained most of his lands. Intermittent unrest in Yorkshire continued, with fighting in 1220 between his men and those of the sheriff, followed in 1221 with him being summoned to help take and destroy
Skipsea Castle during the rebellion of William de Forz. In 1225 he was one of the witnesses to the reissue of Magna Carta and by the end of 1226 had re-entered a monastic order, possibly the
Knights Templar. His Helmsley estates, where he had fortified the castle, then went to his elder son, while Wark, also fortified by him, went to the younger. He died that year, or in 1227, and was buried in the
Temple Church in London. ==Benefactions==