In 845, Nominoë, Duke of Brittany, had defeated Charles the Bald at the Battle of Ballon. A truce had followed, but in 849 Nominoë resumed his offensive against the Franks. He sought to establish full personal control over his duchy and extend its territory. In 851, Frankish garrisons left in the previous year in Rennes and Nantes capitulated to Nominoë, who raided eastwards, ravaging Le Mans. Nominoë then decided to advance to Chartres, but died suddenly, near Vendôme. His successor, his son Erispoe, took command of the Breton force and continued its offensive in alliance with Lambert II of Nantes, a renegade Frank dispossessed by Charles the Bald.