The Breton-Frankish Conflict and the Renewed Alliance of Lambert and Nominoe (850)

By 850, the Breton resistance against Charles the Bald intensifies, as Lambert II of Nantes and his brother Warnar renew their alliance with Nominoe, ruler of Brittany. Their combined forces launch devastating raids into Maine, described by the Chronicon Fontanellense as carried out "with unspeakable fury."

Charles the Bald’s Campaign in Rennes and Nantes (August 850)

• In August 850, Charles marches on Rennes in another attempt to subdue Brittany, but once again avoids direct combat.
• Instead of engaging in battle, he installs Frankish garrisons in Rennes and Nantes, hoping to maintain control through military occupation rather than outright conquest.