Louis the German
Louis the German, c.804–876, king of the East Franks (817–76). When his father, Emperor of the West Louis I, partitioned the empire in 817, Louis received Bavaria and adjacent territories. In the conflict between his brother Lothair I (who succeeded Louis I as emperor) and their father, Louis the German repeatedly changed sides. In 839 Louis I transferred some of Louis's holdings to Lothair; Louis again rebelled and his father died in the ensuing campaign. Louis now joined with his half-brother Charles (Charles the Bald, later Emperor of the West Charles II) against Lothair, who sought to gain supremacy in their kingdoms. They checked Lothair at Fontenoy (841), renewed their alliance (842; see Strasbourg, Oath of), and forced Lothair to accept the Treaty of Verdun (843; see Verdun, Treaty of), which made them independent sovereigns. In 858–59 Louis turned on Charles and unsuccessfully invaded the West Frankish kingdom (France), but both brothers soon directed their attention to the lands of Lothair's heirs, Emperor of the West Louis II and King Lothair of Lotharingia. After King Lothair's death Lotharingia was divided between them by the Treaty of Mersen (870). The death (875) of Louis II renewed the war between Louis the German and Charles; Charles quickly conquered Italy and was crowned emperor of the West. Louis the German, in the course of his reign, defended his frontiers against the Slavs and the Danes and suppressed several revolts of his sons, Carloman of Bavaria, Louis the Younger, and Charles the Fat (later Emperor of the West Charles III).