Part of the reason for the Magna Carta was due to how England chose the Archbishop of Cantebury, the most senior Archbishop of the Church of England. The King's choice was rejected by Rome and King John was excommunicated and eventually has to concede to the Pope's demands. | Part of the reason for the Magna Carta was due to how England chose the Archbishop of Cantebury, the most senior Archbishop of the Church of England. The King's choice was rejected by Rome and King John was excommunicated and eventually has to concede to the Pope's demands. |