And then he had it declared invalid by the Pope. (8/10)

As the last spectacular blunder of his reign, John reneged on his earlier promises to his barons, asking the Pope to declare the Magna Carta an invalid document. The Pope agreed, sparking a civil war between John and his barons once more. Before the war could even conclude, John died, and the nine year old Henry III was crowned king. Henry was managed by William Marshall, Earl of Pembroke and a statesman who oversaw the ruling of England during Henry’s infant years.