Jean VI d'Aumont was a Marshal of France who took part in military campaigns in Burgundy and Brittany during the late 16th century. Specifically, after the assassination of King Henri III in 1589, Aumont aligned himself with the Protestant King Henry of Navarre. He conducted campaigns in these regions against the Duke of Mercœur, who was a prominent figure in the Catholic League, opposing Navarre's claim to the French throne. Prior to this, in 1585, Aumont was appointed by Henri to command an army against forces in Auvergne and Languedoc source: Jean VI d'Aumont - Wikipedia.
Here are some images related to historical military contexts in Brittany:
These campaigns were part of the larger conflict and turmoil in France during the Wars of Religion, where Protestant (Huguenot) and Catholic factions vied for power.