 The medievalist Christopher Starr in his "Oxford" "Dictionary of National Biography" entry on the FitzWalter family, suggests that John was raised by his widowed mother.This may have turned him into "a difficult and dangerous adult".Although by law he could not receive his inheritance until he was 21, in the event, King Edward III allowed him to enter into his estates and titles slightly early, in 1335, when FitzWalter was about 20.