In the real world, not only was the Roman Church opposed to Magna Carta, the supposed Bishops "behind" the charter didn't manage to arrive there until almost forty years after the charter was signed, and only then in response to receiving an agree for an enormous tax increase.
http://www.bl.uk/collection-items/the-papal-bull-annulling-magna-carta
At the link:
[Pope] Innocent III had already sent a string of letters to England berating the [Magna Carta] barons. Now he explained how, by such violence and fear as might affect the most courageous of men, they had forced John to accept an agreement illegal, unjust, harmful to royal rights and shameful to the English people. The Pope declared Magna Carta null, and void of all validity for ever, a judgement which reached England the following month.
Twenty five of the barons supporting it were excommunicated. The Bull [how appropriate] threatened excommunication to anyone who attempted to enforce the charter.
It was Catholic armies which stopped the invasion of the Muslim hordes at the gates of Vienna and Catholic navies which stopped the Muslim hordes off the shores of Lepanto at the very same time that John Calvin was having people beheaded and burned at the stake in Switzerland for disagreeing with his theology.
This doesn't excuse the crimes of the Catholic Church as a corrupt wielder of political power in the two centuries or so before these events, but it does put it into perspective.
Did you know that some episodes of The Brady Bunch are considered part of the Catholic Church's infallible magisterium?
"Aw dad, He wouldn't shoot anybody! He's a real great guy! Jesse James is my hero."