King of the West Franks (843–77), Emperor of Germany (875–77). He was the son of Emperor Louis the Pious. After the death of their father he and his brother, Louis the German, made war on their eldest brother Lothair, who had inherited the title of King of the West Franks. By the Treaty of Verdun in 843 Charles gained that kingdom. He and Louis divided Lothair’s central kingdom between them in 870 by the Treaty of Mersen and Charles gained the imperial title in 875. The internal conflicts of his reign were further complicated by Viking incursions. He was a noted patron of scholarship and the arts.