He issued, therefore, a bull, in which, from the plenitude of his apostolic power, and from the authority which God had committed to him, to build and destroy kingdoms, to plant and overthrow, he annulled and abrogated the whole charter, as unjust in itself, as obtained by compulsion, and as derogatory to the dignity of the apostolic see.

He prohibited the barons from exacting the observance of it: he even prohibited the king himself from paying any regard to it: he absolved him and his subjects from all oaths which they had been constrained to take to that purpose; and he pronounced a general sentence of excommunication against every one who should persevere in maintaining such treasonable and iniquitous pretensions.
The king, as his foreign forces arrived along with this bull now ventured to take off the mask; and, under sanction of the pope's decree, recalled all the liberties which he had granted to his subjects, and which he had solemnly sworn to observe.

But the spiritual weapon was found upon trial to carry less force with it than he had reason from his own experience to apprehend.

The primate refused to obey the pope in publishing the sentence of excommunication against the barons; and though he was cited to Rome, that he might attend a general council there assembled, and was suspended, on account of his disobedience to the pope, and his secret correspondence with the king's enemies; though a new and particular sentence of excommunication was pronounced by name against the principal barons; John still found that his nobility and people, and even his clergy, adhered to the defence of their liberties, and to their combination against him: the sword of his foreign mercenaries was all he had to trust to for restoring his authority.
The barons, after obtaining the Great Charter, seem to have been lulled into a fatal security, and to have taken no rational measures, in case of the introduction of a foreign force, for reassembling their armies.
The king was, from the first, master of the field; and immediately laid siege to the castle of Rochester, which was obstinately defended by William de Albiney, at the head of a hundred and forty knights with their retainers, but was at last, reduced by famine.

John, irritated with the resistance, intended to have hanged the governor and all the garrison; but on the representation of William de Mauleon, who suggested to him the danger of reprisals, he was content to sacrifice, in this barbarous manner, the inferior prisoners only.