A measure of Seymour’s standing in Henry VI’s reign is provided by his service as sheriff for a remarkable seven terms and in four different bailiwicks. By its close he had joined the ranks of the wealthiest gentry of Wiltshire. John came of a distinguished lineage: as the sister and coheir of John, 3rd Lord Beauchamp of Hatch (d.s.p.1361), his great-grandmother Cecily (d.1394), the wife of Sir Roger Seymour, had inherited the Somerset manors of Hatch Beauchamp, Shepton-Beauchamp, Murifield and a third part of Shepton Mallet, all of which eventually passed down to him.
Seymour can have barely attained his majority when he was elected to the first Parliament of Henry VI’s reign, as a representative of the Wiltshire borough of Ludgershall. There, his maternal grandfather Sir William Sturmy, as chief steward of Queen Joan’s lands and custodian of Ludgershall itself, exerted considerable influence. This much is clear from the identity of Seymour’s colleague in the Commons, namely, his uncle of the half-blood, John Sturmy* (Sir William’s illegitimate son), who was also attending Parliament for the first time. Another newcomer was his mother’s cousin Robert Erle*, who accompanied him to Westminster as MP for Great Bedwyn. The introduction of the three kinsmen to the Lower House was effected by Sir William himself, sitting for the county in what was his 12th and final Parliament; as a former Speaker and established parliamentarian he was well qualified to show the novices the ropes. They in turn would have been constantly at hand to assist the elderly knight now reaching the end of his career.
Seymour may have seen military service in France in his youth, before his first Parliament, but the earliest record of him actually doing so dates from February 1424. He then undertook to serve for two months with his own contingent of three archers in the army led by Humphrey, duke of Gloucester, to recapture the fortress at Le Crotoy.
On 16 Apr. 1427 the keepers of passage in the ports of south-east England, including London, were authorized to permit Seymour to embark on a pilgrimage to Rome.
For the time being, Seymour appears to have been content with his lot and took no legal action to contest his grandfather’s settlements on Erle and John Sturmy. The Sturmy inheritance had increased his wealth, so that when it came to assessing the subsidy on landed incomes levied in 1451 (which he was commissioned to do), he could put himself down as in receipt of an income of £180 p.a.
That same spring of 1434 Seymour was listed among the gentry of Wiltshire required to take the oath not to maintain malefactors,
In 1447 Seymour’s control over the bulk of the former Sturmy estates met with a challenge from his cousin William Ringbourne, whose mother had recently died and who evidently considered Seymour’s share to be disproportionate. Their disagreement led to a fresh partition of their late grandfather’s lands in Hampshire and Wiltshire, which inter alia required the legal transfer of the manor of Figheldean, which was held in chief; Seymour was fined £12 for completing this without the King’s permission.
Seymour was well regarded by some of his peers. In the 1440s he had been asked to be an arbiter in a dispute between William Warbleton* and William Fauconer; Reynold, Lord de la Warre, (Sir) James Luttrell (a kinsman by marriage), and John, Lord Stourton, all asked him to be their feoffee, and he attested deeds for (Sir) John Lisle II*.
Understandably, the new regime regarded Seymour with suspicion, removing him from the bench in Wiltshire and declining to appoint him to ad hoc commissions. More seriously, the wardenship of Savernake forest was taken away from him: as early in the reign as 9 Apr. 1461 the forest was committed to one of the new King’s supporters. The process by which he eventually recovered the hereditary office, proved complicated,
Seymour died on 20 Dec. 1464.
Seymour’s widow, Isabel, to whom he had been married for 40 years, took a vow of perpetual chastity in the collegiate church of Westbury by Bristol in the presence of Bishop Carpenter of Worcester on 3 June 1465.
The Seymour cadets, Humphrey and his brother Ralph, were married to daughters and coheirs of Thomas Winslow I* (d.1462), in an alliance probably cemented during the lifetimes of their fathers. Through his eldest son our MP was great-great-grandfather of Jane Seymour, queen to Henry VIII and mother of Edward VI, and of her brother Edward, duke of Somerset, the Protector.
