Charlemagne
He was king of the Franks from 768, and king of the Lombards from 774. He was crowned Imperator Augustus (Emperor) in Rome on Christmas Day by Pope Leo III in 800, starting the Holy Roman Empire, that they hoped would be a kind of second Western Roman Empire (while the Byzantines in Constantinople were still keeping up the Eastern Roman empire). With many wars, Charlemagne spread his empire across much of Western Europe.