William de Thornaco was a Priest in the Roman Catholic Church.
Bishop Robert Grosseteste had instituted a program of visitation, a procedure normally reserved for the inspection of monasteries.
This scheme brought him into conflict the aforementioned people who vigorously disputed his claim to exercise the right of visitation.
The dispute raged hotly from 1239 to 1245, with the chapter launching an appeal to the papacy.
In 1245, while attending the First Council of Lyons, the papal court ruled in favour of Grosseteste.