Of unknown origins, Gregg became one of the wealthiest and most influential merchants of Hull in the early fifteenth century although, apart from his will, the evidence relating to him is surprisingly slight. He should probably be identified with the individual of that name who exported cloth and imported wax through the port there in 1391-2, but he did not purchase the freedom of the town until 1398.
It is possible that a desire to escape the consequences of litigation prompted Gregg to make a couple of settlements in February 1431. First, he assigned a property in Marketgate and £80 in cash to his daughter, Agnes; secondly, he gifted goods and chattels to Ralph Forne, subsequently one of his executors.
In September 1437, shortly before his death, Gregg purchased three tenements in Market Street from the feoffees of John Grimsby. Grimsby had died intestate earlier that year but he may have intended that these holdings, along with others in the town obtained by Gregg, should endow a chantry. It is far from clear that Gregg acquired these properties in order to fulfil the wishes of his fellow merchant, since he did not explicitly mention Grimsby in his will.
Joan did not long outlive her husband. Her own will of 3 Dec. 1438 closely followed the provisions of his will and reveals her to have been a wealthy woman. She disposed of cash bequests to the value of £240 and set aside £40 for an ostentatious funeral in Gregg’s burial place, the chapel of the Holy Trinity. Among other bequests, she assigned sums to the religious guilds that the MP had remembered in his will, to the poor and towards the repair of roads and the building of a water conduit in Hull. She also left her thirty-second share of a ship, the George, to Gregg’s former apprentice and feoffee, Stephen Gildhous, and William Arnald: whether the lack of a similar bequest in the MP’s will means that he had not possessed a like interest in local vessels is impossible to tell. In fulfillment and augmentation of her husband’s wishes, Joan confirmed that the income of the properties formerly belonging to John Grimsby, along with others in the town once held by the draper, John Bilton, was to support a chantry priest in Holy Trinity chapel, as well as 13 paupers in the Maison Dieu, an almshouse she had built on Old Kirklane. For her executors, she chose the same men appointed by her late husband, along with Gregg’s former apprentice Gildhous, the chaplain John Brig and Thomas Bynham. She was dead by 30 Dec. when her will was proved.
