Of the men who represented Guildford in this period Thirsk was perhaps the one most closely involved in the day-to-day administration of the borough. On the basis of their name, his family may have originated from Thirsk in Yorkshire, but there is no suggestion that William himself maintained contacts outside the south-east. On the basis of Thirsk’s frequent service as an attorney in the royal law courts it seems probable that he received some legal training, and it may also have been this qualification which gained him his appointment as town clerk of Guildford in December 1426.
It is nevertheless possible that his claim, recorded in the court of common pleas in early 1446, that four years earlier his home had been at Chertsey, rather than at Guildford, may have had some basis in fact, for in September 1444 he was one of those employed by the abbot and convent of Chertsey to draw up a new rental of the abbey estates.
Little is known of Thirsk’s personal life, although the three tuns of red wine that he purchased from the London merchant Thomas Grey in February 1437 at a cost of £16 may afford a glimpse of both his lifestyle and his economic circumstances, not least since £2 6s. 8d. of the purchase price remained unpaid 11 years later.
