King John Was a Monster – But Did He Really Murder His Own Nephew?

Sometime after the summer of 1202, a young teenage prince, Arthur of Brittany, vanished inside the vast dominions ruled by his uncle, John, King of England. He was John's nephew, a Plantagenet prince and, according to some interpretations of royal succession, the man who should have inherited the English throne instead of him – in 1199, both John and Arthur had plausible claims to inherit the throne from the deceased Richard I.

Arthur had rebelled against his uncle and been captured. Whatever happened next, Arthur disappeared for good. Naturally, the blame for the not-so-mysterious disappearance (and presumed death) of young Arthur fell at the feet of his uncle – the man who stood to gain the most from his murder.

For King John, the mystery was particularly damaging because it seemed to fit a reputation that was already taking shape. His reign saw the loss of Normandy, a bitter conflict with Pope Innocent III, financial and military pressure on his barons and, eventually, the rebellion that forced him to accept Magna Carta in 1215.

"This is a man you could not trust," says medieval historian Professor Nicholas Vincent, speaking on the HistoryExtra podcast. "He betrayed his father. He betrayed both his wives. He betrayed his closest friends."