Robert is first recorded in July 1396 standing surety for his brother John, who was defending himself in an action for debt brought by the executors of Bishop Brantingham of Exeter. John had sat in seven Parliaments for five different Cornish boroughs (including Liskeard) and was already a figure of some consequence in the shire, having served both as under sheriff and alnager, and may well have been instrumental in securing Robert’s own election to the Commons. It was probably because of John’s close association with Sir Richard Cergeaux that after the latter’s death, by a grant dated 30 Dec. 1397, while Parliament was in recess, Robert was able to obtain a share in a lease at the Exchequer of the estates falling to two of Cergeaux’s daughters, who were both minors. He and his co-lessee paid £100 for the marriage of the girls, but no doubt made some financial gain out of the transaction, for although one of them died shortly afterwards, the other, Alice, was contracted first to Guy St. Aubyn and then (in 1406 or 1407) to Richard de Vere, earl of Oxford. Robert and his brother both had some connexion with Nottinghamshire, and, indeed, may well have belonged to a branch of the family which took its name from Syerston in that county. It was as ‘of Nottinghamshire’ that in 1398 Robert stood surety in Chancery for a servant of the farmer of Northolt rectory, Middlesex, and he was similarly designated when he appeared in the same court on other occasions in the course of the next ten years.
Nevertheless, Syreston retained contacts in Cornwall. In 1402 he was engaged in another transaction on behalf of his brother John, and like him he had a financial interest in tin mining (in June 1409 nearly 1,000 lbs. of tin were assessed for coinage at Lostwithiel in his name). Ten years later Robert, acting as executor of John’s will, took legal action against Sir John Arundell of Trerice for recovery of a debt of £43 6s.8d. In the meantime, in 1407 and 1408, he had provided mainprise both in Chancery and in the King’s bench for another Cornishman, Richard Allet.
