The Sydenhams were a prolific west-country family, who even by the early years of the fifteenth century had established a number of cadet branches in the region.
Henry Sydenham’s death left his son and heir a minor in the custody of his feudal overlord, Sir Hugh Luttrell† of Dunster, who in about 1427 granted the keeping of both heir and lands to Master Simon Sydenham. It is possible that by this date the young John was already living in the household of his uncle (then dean of Salisbury), for in about 1425 he was recorded among the men summoning two defendants into Chancery on behalf of the sheriff of Wiltshire. Certainly, he had forged ties in the circle of the leading Wiltshire magnate Walter, lord Hungerford†, by November 1431, when (styled a gentleman of Wiltshire) he stood surety in the Exchequer for Richard Milborne*, who like Master Simon Sydenham was one of Hungerford’s feoffees.
By the autumn of 1431, John had come of age, and that year his uncle, then newly elected bishop of Chichester, brokered an agreement between him and his cousin and coheir Walter Pauncefoot, under the terms of which the lands of John Whiton were divided up in such a way that Sydenham gained the Whiton holdings in Somerset (consisting principally of the manors of Bossington and Timbercombe, together said to be worth at least £22 p.a.) in their entirety.
While Sydenham’s later inclusion in the quorum of the peace in his native Somerset may suggest that, like his grandfather, he had received some training in the law, he does not seem to have ever actively practiced as a lawyer. Instead, he lived the life of a country gentleman, and periodically put his knowledge at the disposal of his friends and neighbours, for whom he acted as a feoffee and a witness to their title deeds.
It is not clear to what circumstance Sydenham owed his first return to the Commons for the decayed borough of Old Sarum, but it seems very likely that Stourton influence played a part. Since 1447 Joan Sydenham’s cousin John, recently created Lord Stourton, had had custody of the ruined castle and lands belonging to it, and he may well have taken the opportunity to secure a parliamentary seat for her husband.
Nothing is known of Sydenham’s role in the proceedings of the Lower House, and it seems that it was only at the time of his third return, to the Reading Parliament of 1453, that he became drawn into public affairs on a broader scale. On the final day of the first session he was added to the Somerset county bench. The wider crisis that engulfed the realm in the loss of Gascony and the King’s mental collapse that summer, was followed for Sydenham by the personal grievance of having to sue the sheriff, Nicholas Latimer*, for his parliamentary wages (amounting to the substantial sum of £33). These remained unpaid even in the spring of 1455, a year after the dissolution.
In 1467 Sydenham was returned to the Commons for at least the sixth time, but he was not to see this Parliament out. On 6 Nov. the assembly was prorogued to meet once more on 5 May 1468, but by then he was dead, having died a month earlier on 4 Apr. He was succeeded by his eldest son, Walter, then aged 25, who eight years earlier, despite his youth, had attested the Somerset parliamentary elections. But Walter survived his father by little more than two years, leaving as his own heir his infant son John.
