John II the Good: Captivity, Internal Crisis, and the Treaty of Brétigny (1350–1364) · HIGH MIDDLE AGES
The truce from Brétigny has a perverse effect: thousands of fighters find themselves unpaid. Structured bands, called Great Companies, live off the country, occupy places, extort roads, and paralyze the economy. War becomes permanent insecurity.
Often English or Gascon, these groups claim England or Navarre depending on opportunity. They serve rivalries: Edward III can let mercenaries act under Navarrese colors, which nourishes popular hostility toward “English” and also discredits Charles II of Navarre, perceived as complicit.
Captains seize fortresses in their own names. The keep of Rolleboise becomes a celebrated example: controlling a place means controlling a circulation axis and thus levying tolls, ransoms, and tribute. The companies also establish themselves on major routes, notably the Saône and Rhône valleys, a north-south commercial corridor reinforced by papal presence in Avignon.
One attempts to buy them: they often cash in without leaving. One attempts to employ them elsewhere: they return. One attempts to oppose them: the strategy fails.
On April 6, 1362, royal troops are beaten at Brignais. The defeat illustrates the limits of an army dependent on fragile recruitment: mercenary contingents can leave the battlefield, and victory turns to collapse.
The episode also costs politically: one must pay ransoms to free captured figures, like William of Melun.