[3][2] The site was occupied by a manor house in 930; Jasper Tudor, Duke of Bedford & Earl of Pembroke, died there in 1495.
Part of the original plans for a very grand residence were "well advanced",[4] with a licence to crenellate being granted in 1508,[5] before the 3rd Duke of Buckingham was beheaded for treason in 1521, by order of King Henry VIII.
Following the 3rd Duke's death, Thornbury was confiscated by Henry, who stayed there for ten days in August 1535 with Queen Anne Boleyn.
Between 1966 and 1986 the castle was operated as one of the UK's top restaurants by Kenneth Bell with staff including food writer Nigel Slater[9] and MasterChef New Zealand judge Simon Gault[10] early in their culinary careers.
[12] In August 2022 the future of Thornbury Castle was called into question when the Great Western Society's 4709 Group bought the locomotive with the intention of donating the boiler to its project to re-create a GWR 4700 Class.