Sir Bertram Monbourcher was the grandson and namesake of a Breton knight who came to England in the retinue of John, duke of Brittany and earl of Richmond (d.1333). From his patron, Sir Bertram the elder received the manor of Hammerden, together with other property in the Sussex villages of Filsham, Morley and Cortesley. Furthermore, through his marriage to Joan, the daughter and heir of Sir Gerard Charron, he gained immediate possession of the manor of Sutton-on-Trent in Nottinghamshire, and eventually succeeded to his father-in-law’s extensive estates at Horton in Northumberland as well. Sir Bertram also acquired the manor of Dalton in Yorkshire, and thus firmly established his family as landowners of some consequence. Not much is known about his son, Reynold, who died shortly before 1350, while his own son and heir, Bertram, the subject of this biography, was still a minor. The young man was probably just about to take seisin of his inheritance when, in February 1358, he entered into a marriage contract with Sir Gerard Widdrington and his brother, Roger, who offered him securities of £300, presumably as a guarantee that they would abide by the terms of the arrangement. They also bound themselves in similar sums to their feudal overlord, Maud, countess of Pembroke, so property may well have changed hands at this time. Bertram evidently had to pay quite handsomely for the hand of Roger’s elder daughter, Christine, for as late as 1364 he still owed his father-in-law 622 marks, secured on the revenues of his holdings in Sussex.
Meanwhile, in 1359, Bertram took to the field for the first time in the army which Edward III led to France; and in the following year he was present at the siege of Paris. He had been knighted by April 1364, and may, perhaps, have returned to France in the retinue of Henry, Lord Scrope of Masham, whom he served at about this point in his career. A prominent position in Northumbrian society, already assured by his ownership of estates in Horton, was greatly enhanced by his wife’s impressive inheritance. His influence as a landowner grew appreciably, and he was soon chosen to represent the county in Parliament, entering the House of Commons for the first time in 1373. His appointment to the shrievalty of Northumberland one year later proved more of a mixed blessing, since repeated raids by the Scots, together with the general state of disorder and disease endemic along the march, made it difficult for him to raise the required farm. By March 1376 his attorney had been consigned to the Fleet prison pending a satisfactory settlement of his accounts, although John, Lord Neville, secured his release by guaranteeing Sir Bertram’s readiness to appear in person before a panel of auditors at the Exchequer. The knight’s finances were indeed strained during this period, as he also undertook to make a contribution towards a royal loan of £2,000 promised by a group of leading northerners. In the end only £500 reached the King’s coffers, so his share may have been somewhat reduced. Sir Bertram sat again in Richard II’s first Parliament (Oct. 1377), and was prevailed upon during the session to undertake a second term as sheriff. This proved an even more thankless and unrewarding task than before, since he himself rather than his attorney ended up in prison, and it was only on the intervention of the earl of Northumberland, in March 1382, that he was released on bail. By then, however, the government had at least come to appreciate the scale of his difficulties and a writ of supersedeas was issued on his behalf, halting any further legal action over his arrears.
During his third and last Parliament, in October 1386, Sir Bertram gave evidence at St. Margaret’s chapel, Westminster, on behalf of Richard, Lord Scrope, who was then engaged in his celebrated dispute with Sir Robert Grosvenor over the right to bear the same coat of arms. As a former retainer of the Scrope family, under whose banner he may have served as recently as 1385, on Richard II’s ill-fated campaign against the Scots, he naturally sought to provide as favourable a testimony as possible. Perhaps reassured by the Crown’s previous concessions regarding the reduction of his farm, Sir Bertram again agreed to serve as sheriff of Northumberland in January 1387, although he did not live to present his accounts, which were submitted by his son. He died on 6 Aug. 1388, leaving the estates which he and his wife had inherited in Durham, Northumberland, Nottinghamshire, Sussex and Yorkshire to Bertram Monbourcher the younger. Neither the latter nor his son or grandsons survived long enough to gain much advantage from the wealth and influence at their disposal. By June 1425, the male line of the Monbourcher family had died out altogether, and it was to Isabel, Sir Bertram’s only daughter, that everything then passed. She was herself succeeded shortly afterwards by the son of her second marriage (to the rich and influential crown servant, Robert Harbottle), a young man to whom Sir Robert Ogle had shrewdly married his daughter in anticipation of such dynastic accidents.