The Mohun's had as a family member and ally William Brewer who had himself flourished in royal service under King John.
This new generation of Mohuns were born into a world that was being shaped by John's famous charter.
Henry, as did previous monarchs regularly used council meetings to discuss affairs of state, in Henry’s reign these meeting resulted in the early formation of an English Parliament. During the thirteenth century these assemblies were always summoned by the king and generally he consulted only a small council, but by requiring the wealthy barons to help govern, Henry strengthened their powers and in time they came to call themselves the Great Council. These men grew to think that the king must consult the council and when decisions were made without their consultation they developed a sense of being excluded from the work of government in which they felt entitled to participate.