Seeking revenge, Charles the Bald invaded Brittany with an army drawn from both the western and eastern parts of the Frankish empire. Erispoe, Nominoe's son and successor, intercepted Charles at the Battle of Jengland (851). As the Bretons decisively defeated the Franks, Brittany became effectively independent of the Frankish Empire, making Erispoe the first king of Brittany. In 856, the Kingdom of Brittany and the Frankish Empire allied themselves to counter the Norman invasions. But Erispoe was murdered the same year by his cousin Salomon who took the throne of Brittany and allied himself with the Normans to capture the Frankish city of Le Mans.