Seems about as good a place as any for this:http://www.medievalsoldier.org/dbsearch/
This gives a record of soldiers serving during the 100 years war.
I once researched my family back 5 generations. With the exception of that part of my family which comes from France almost all of my ancestors up to 5 generations back came from Warwickshire, Gloucestershire or Oxfordshire.
Having used the above search I found mention of soldiers with my name & that of both my paternal and maternal grandmothers. This you may expect, however the search engine gives which Captain they served under and one of them served directly under the Earl of Gloucester and an other under the Earl of Shrewsbury. Given soldiers were raised within the manors held then they could be ancestors. Probably a coincidence but with a look for anyone interested in genealogy.