Wallingford is a market town and civil parish in the upper Thames Valley in England. Until 1974 it was in Berkshire, but was transferred to Oxfordshire in that year. The town's royal but mostly ruined Wallingford Castle held high status in the early medieval period as a regular royal residence until the Black Death hit the town badly in 1349. Empress Matilda retreated here for the final time from Oxford Castle in 1141. The castle declined subsequently, much stone being removed to renovate Windsor Castle instead. Nonetheless the town's Priory produced two of the greatest minds of the age, the mathematician Richard of Wallingford and the chronicler John of Wallingford.
For more information, see the EN Wikipedia article Wallingford, Oxfordshire.. The sections titled "Geography", "Character and local government", and "History" are of note.