Battle of Jengland: Erispoe defeats Charles the Bald near the Breton town of Jengland.

The Battle of Jengland took place on 22 August 851, between the Frankish army of Charles the Bald and the Breton army of Erispoe, Duke of Brittany. The Bretons were victorious, leading to the signing of the Treaty of Angers in September 851 and the recognition of Erispoe as the legitimate ruler of the Bretons under Charles the Bald.

Erispoe was Duke of Brittany from 851 to his death. After the death of his father Nominoe, he led a successful military campaign against the Franks, culminating in his victory at the Battle of Jengland. He is subsequently referred to as "King of Brittany".

Charles the Bald, also known as Charles II of West Francia, was a 9th-century king of West Francia (843–77), King of Italy (875–77) and emperor of the Carolingian Empire (875–77). After a series of civil wars during the reign of his father, Louis the Pious, Charles succeeded, by the Treaty of Verdun (843), in acquiring the western third of the empire. He was a grandson of Charlemagne and the youngest son of Louis the Pious by his second wife, Judith.