King John, when he saw that he was deserted by almost all, so that out of his regal superabundance of followers he scarcely retained seven knights, was much alarmed lest the barons would attack his castles and reduce them without difficulty, as they would find no obstacle to their so doing; and he deceitfully pretended to make peace for a time with the aforesaid barons, and sent William Marshal Earl of Pembroke, with other trustworthy messengers, to them, and told them that, for the sake of peace, and for the exaltation and honour of the kingdom, he would willingly grant them the laws and liberties they required; he also sent word to the barons by these same messengers, to appoint a fitting day and place to meet and carry all these matters into effect. The king's messengers then came in all haste to London, and without deceit reported to the barons all that had been deceitfully imposed on them; they in their great joy appointed the fifteenth of June for the King to meet them, at a field lying between Staines and Windsor. [i.e. Runneymede] Accordingly, at the time and place pre-agreed on, the King and nobles came to the appointed conference, and when each party had stationed themselves apart from the other, they began a long discussion about terms of peace and the aforesaid liberties. At length, after various points on both sides had been discussed, King John, seeing that be was inferior in strength to the barons, without raising any difficulty, granted the underwritten laws and liberties, and confirmed them by his charter.
 
Source: Roger of Wendover, Flowers of History, translated by J.A. Giles (London: Henry G. Born, 1849), Vol. II, pp. 308-309