Originally a family of at best middling gentry rank, in the 1440s the St. Johns saw one of their branches propelled to sudden prominence by the marriage of Oliver St. John to Margaret Beauchamp of Bletsoe, widow of John Beaufort (d.1444), duke of Somerset. The place of the Taunton MP of 1447 in the family’s convoluted pedigree has not been established. It has been suggested that he came from the branch of the family resident at East Luccombe in Somerset, and was thus a son or brother of Edward St. John (d.1457), but no evidence to corroborate this supposition has been discovered.
Rather, it seems that Thomas may have been the son of John St. John, a London draper. No details of his education have been discovered, but he does not appear to have followed his father into trade, and instead became attached to the royal household. In 1440 he and one John Ashfield were appointed in survivorship to a corrody in the priory of Wenlock.
It may have been the influence of Wenlock, by then an usher of the queen’s chamber, that saw St. John returned to the controversial Parliament of 1447 for Cardinal Beaufort’s borough of Taunton. It is not clear how the election came about, but it is probable that the ailing cardinal played little part, and that others in the royal household exercised their patronage in his name. In the Commons, St. John not only joined Wenlock himself, but also another acquaintance from the marches, the lawyer William Bastard*, whom he had encountered two years earlier in the course of the transactions surrounding his old friend Ashfield’s acquisition of the Oxfordshire manor of Heythrop (part of the inheritance of his wife, the younger daughter of John Wilcotes†).
St. John’s connexion with Ashfield was to remain central to his documented career. In November 1447 he joined Ashfield’s nephew Thomas Gryme in finding sureties for his friend’s purchase at the Exchequer of the herbage of the royal forest of Merioneth, and within a few years Ashfield himself was acting as a feoffee of some of the property that St. John stood to inherit in the city of London.
