I think the point that gets missed is that the medieval times in England, under, I believe, the Same John mentioned in Robin Hood, signed the Magna Carta, which is part of the foundation for the U.S..
But if memory serves me correctly, John did sign the Magna Carta voluntarily, he was forced if he wanted to live.
He was one of the worst kings England ever had. He squandered almost all the lands his father had gained and this is why his nickname is "John Lackland".
He signed the Magna Carta under duress, and Pope Innocent III sided with him, annulling it after John complained that the charter compromised the Pope's rights as a lord (England being a vassal state of the Vatican). This led to civil war.
John wasn't exactly the cartoon villain that the legends portray him as, but he was cruel, autocratic, and not a little corrupt.