King John
After his brother, King Richard the Lionheart, left to fight in the crusades in the Holy Land King John was forced to become King (in Richard's absence). He was not prepared. Instead he had to tax people to pay for his brother's army which made him unpopular and then after his brother's death he managed to upset most of the Lords at his court. He was forced to sign a document 'The Magna Carta' which made him and all subsequent Kings and Queens of England follow a set of rules which made it really difficult for him to do what he wanted when he wanted to do it.