Although Gatyn was probably born a Londoner, he soon developed strong connexions with Guildford, both through his trade as a fishmonger and his subsequent investment in local property. He first appears in May 1368, when, described as ‘of London’, he stood surety for John Hanekyn in Chancery. Four years later he was himself being sued for trespass in Surrey and spent a brief period in prison until his own mainpernors offered bail of £40 on his behalf. By October 1376 Gatyn had become a member of the guild merchant at Guildford, whose expenses at this time included a payment of 3s. arising from the cost of meeting unspecified fines incurred by him and by other prominent townsmen.
Other legal and financial affairs continued to occupy him in the capital and eventually took him abroad. In July 1384 he was named among the feoffees of Joan, widow of William Spencer, a fellow citizen and fishmonger of London, although by August 1386 all his duties in this respect had been fulfilled. On 3 Oct. 1390 he received permission to go overseas, taking 40s. for his expenses, and on the same day he was given a royal licence to negotiate a letter of exchange worth £6 with a Lombard merchant. Very little is known of Gatyn’s career after this date. In September 1400 he acted as a surety in Chancery for Hugh Ryebread, another fishmonger, but except for his last two elections to Parliament nothing more is heard of him.
