Lothar I

(born 795—died Sept. 29, 855, Abbey of Prüm, Ger.) Frankish emperor. The eldest son of Louis I (the Pious), he was crowned king in Bavaria (814) and coemperor with Louis (817). Lothar participated in the rebellion against Louis in 830 over the emperor's efforts to alter the succession plan, and he was returned to Italy after the revolt's failure. He led a second revolt against his father and deposed him (833), but Louis was restored to power the next year, and Lothar's rule was restricted to Italy. On his father's death (840) he attempted to gain sole control over the Frankish territories, but his brothers, Louis the German and Charles II (the Bald), defeated him (841). The Treaty of Verdun gave Lothar the middle realm, or heartland, of the Frankish dominions (from the North Sea to Italy) and the imperial title.

Source: Encyclopedia Britannica