When the Carolingian empire was divided in 843, Nominoe took advantage of the confusion to consolidate his territory. In alliance with Lambert II of Nantes and the Viking warlord Hastein, Nominoe's son Erispoe defeated the Franks at the Battle of Messac. In 845 the Breton army under Nominoe defeated the forces of Charles the Bald, King of West Francia (France), at the Battle of Ballon, in the eastern part of Brittany near Redon and the Frankish border. Nominoe gained control over the major towns of Rennes and Nantes, which had previously formed part of the Frankish border zone known as the "Breton March".