The Magna Carta, The Marshall and the Master of the Temple

Watching the movie Ironclad the other night, I did alittle Wikipedia as the bodies were cloven. It would appear that one of the great knights of the era, William Marshall, whose tomb is in the London Temple, was present and an advisor to King John when he signed over rights to all freemen in the 1200's document. This document which initiated Hadeas Corpus, the right to be charged when held, was a great step away from the idea of King as Gods magistrate. The Master of the Temple was also present. So while these men were not on the side of the Lords and freemen, it is easy to think that this important charter, giving powerful rights to guildsmen may have contributed to the transition from Templars to Freemasons and to the rights of man. Marshall, who had fought in the Holy Land, was made a Templar on his deathbed. Does anyone have any comments further on the subject?