[Benjamin Rial]

For the historical society that I work with, one of my personas is a late 15th century English mercenary. Part of his history is getting in a bad fisticuffs with a reeve back in Old Blighty and accidently killing him. Quite naturally this makes him an outlaw and he flees. Later that year he signs on with John de Vere, Earl of Oxford to serve Henry soon to be the VII at Bosworth and later Stoke. I have read of a reference about some outlaws being granted a "Charter of Pardon" for service to the crown in the Osprey book "English Longbowmen".
In order to further expand my personal kit and educational presentation, I would like to create a reasonable representation of such a thing. Unfortunately, I have no clear idea of what one may look like, nor what the wording would be. My searches have thus far resulted in nothing solid.
Any assistance with this in the form of sources, wording, or examples, would be greatly appreciated.