Someone was keeping records on who was where, doing what and when in England from 1369-1453, military-wise. A long time ago, yes? Some of the records survived and are now online, made available by the Arts and Humanities Research Council (AHRC).
Look for yourself: The Soldier in Later Medieval England
Two soldiers are listed that I might be related to. William Barger was an archer, serving 1395-1397 under Sir Stephen le Scrope. Geoffrey Barger served in 1404 for Lord Thomas Berkeley, something to do with Keeping of the Sea.
Sounds difficult, this keeping-of-the-sea task, n’est pas? Geoffrey must have done a good job since all the seas are still there, in the same place that they were just over 600 years ago.