Roger married a major heiress,
Helen of Galloway, the eldest of the three daughters of
Alan, Lord of Galloway. On her father's death in 1234, he acquired her share of the paternal inheritance, which consisted of the hereditary office of
Constable of Scotland and one-third of the lordship of
Galloway. The title of
Lord of Galloway, however, went through Helen's half-sister
Devorguilla to her husband
John Balliol. In 1235
the Galwegians rebelled under
Gille Ruadh, not wanting their land divided, but the rebellion was suppressed by King
Alexander II of Scotland. The Galwegians revolted again in 1246, following the death without children of Helen's sister Christina, first wife of
William de Forz, 4th Earl of Aumale. Further unrest in 1247, possibly due to his strict rule, found de Quincy trapped in a castle, from which he escaped to obtain help from King Alexander in suppressing the rebellion. Although actively managing his lands in Scotland, despite being Constable after this time he seems to have had little further involvement in Scotland's politics and wars. In England he also steered clear of politics initially but was gradually drawn into the baronial opposition to the rule of King
Henry III, He joined with other nobles in 1239 and 1246 in written remonstrances to the
Pope about papal interference in English affairs. In 1258, he was elected by the barons to the twelve-member commission charged with overseeing the revised constitution of the
Provisions of Oxford and was appointed also to the committee to arrange the financial aid promised to Henry. In 1259 he led a delegation to
St Omer that forbade the King's brother
Richard, Earl of Cornwall from returning to England unless he swore to observe the Provisions of Oxford. After this de Quincy played little part in national affairs. He died aged about 69 on 25 April 1264, eighteen days after the outbreak of civil war, and was buried at
Brackley. Having no male heir, the earldom of Winchester became extinct and his estates were divided among the husbands of his three daughters. ==Family==