The Carolingian Empire (800–888) was a large empire in western and central Europe during the early Middle Ages. It was ruled by the Carolingian dynasty, which had ruled as kings of the Franks since 751 and as kings of the Lombards of Italy from 774. In 800, the Frankish king Charlemagne was crowned emperor in Rome by Pope Leo III in an effort to revive the Roman Empire in the west during a vacancy in the throne of the eastern Roman Empire. After a civil war (840–43) following the death of Emperor Louis the Pious, the empire was divided into autonomous kingdoms, with one king still recognised as emperor, but with little authority outside his own kingdom. The unity of the empire and the hereditary right of the Carolingians continued to be acknowledged.