Wallingford Castle was a major royal castle and stronghold, originally  built around 1067-1071 by Robert D’Oilly, on orders from William the Conqueror, it was much enlarged during the Middle Ages, but was finally destroyed by Oliver Cromwell.  The castle was important in the war between Empress Matilda, Henry I’s daughter and royal heir, and her cousin Stephen, who had seized the throne. Stephen laid siege to Matilda’s supporters at Wallingford Castle many times.  Many royals and their associates lived and entertained at the castle, including Richard Earl of Cornwall, Henry III’s brother, who was the richest man in England.  In 1243 the Earl of Cornwall’s nuptial feast for his wedding to his second wife Sanchia took place at Wallingford with Henry III present. In 1249 Richard celebrated Christmas at Wallingford, and the following year, 1250, probably saw the final closure of Wallingford’s Mint. 

The mint was located within the castle, and had continued its activity during the 11th and 12th centuries,  and in the reign of Henry III it had a staff composed of four moneyers, four keepers, a clerk and two assayers, who in 1249 were ordered to appear before the barons of the Exchequer, perhaps in connection with a large issue of coinage authorized in that year, half the profits of which were given to Richard Earl of Cornwall.  No Wallingford coin of a later date than the reign of Henry III has been found.  Wallingford is the only mint where production of 3ab1 coins exceeded that of 3b - perhaps it closed earlier than other provincial mints.