Son of Louis the Pious, Lothair was declared sole heir and associated with the Empire in 817. Lothair at this time is sent to Italy, he is crowned emperor by the pope. Lothair I revolted against his father Louis I the Pious who wanted to make new arrangements in favor of his youngest son Charles. With his two brothers, Louis the German and Pepin, he dethroned him twice in 830 and 833, but twice he was forced to return the crown to him. Remaining sole emperor on the death of his father in 840, he wanted to invade the states of his two brothers, but they joined forces against him and defeated him at Fontenay-en-Puisaye in 841. They imposed on him the division of Verdun in 843 which granted him the imperial title and a long and narrow Lotharingia going from the north to the south of Europe. Lothair died in Prüm in 855.
Considered lacking in charisma and discernment, Claudius – son of Drusus – nonetheless remains a scholar whose reign was fundamental to the Roman Empire. Indeed, he initiated various reforms favoring the strengthening of imperial powers and built the port of Ostia and new aqueducts in order to solve