Charles the Bald, also known as Charles II, was a 9th-century king of West Francia (843–877), King of Italy (875–877) and emperor of the Carolingian Empire (875–877). 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.

Louis the Pious, also called the Fair and the Debonaire, was King of the Franks and co-emperor with his father, Charlemagne, from 813. He was also King of Aquitaine from 781. As the only surviving son of Charlemagne and Hildegard, he became the sole ruler of the Franks after his father's death in 814, a position that he held until his death except from November 833 to March 834, when he was deposed.