After John's failed attempt to reconquer Normandy, the baron had the straw that broke the camel's back. John caught wind of a coup and did everything he could to stop it, from buying time to gain support from the pope, to declaring himself a crusader in hopes of gaining protection policy. None of this worked and the Baron's "Army of God" marched on London, taking the cities as they advanced. John was forced to negotiate peace talks, as more of his royalists left to join the barons. In June 1215, unbeknownst to John, he and the rebel leaders drew up the framework for the English constitution, the Magna Carta. This proclamation attempted to settle the Baron's problems with John, as well as to address issues concerning Church law and the rights of men. Neither group intended to adhere to the terms of this potential peace, as Innocent III excommunicated the barons, resulting in the war breaking down.