 The castle was besieged in 1216 during the civil war between King John and rebellious barons , who were supported by France . It was successfully captured after Prince Louis , the future Louis VIII , attacked it with siege engines for twenty days , forcing the garrison to surrender . After being retaken by royal forces the subsequent year , it was given to Richard , Earl of Cornwall , beginning a long association with the Earldom of Cornwall and the later duchy . Richard redeveloped the castle as a palatial residence , and made it the centre of the earldom 's administration . Edward III further developed the castle in the 14th century and gave it to his son , Edward , the Black Prince , who expanded the hunting grounds . The castle was also used to hold royal prisoners , including John II of France and rival claimants to the English throne . 
