"Charlemagne | Holy Roman emperor [747?-814]" "Charlemagne | Holy Roman emperor [747?-814]" Charlemagne | Holy Roman emperor [747?-814] | Britannica.com "Charlemagne | Holy Roman emperor [747?-814]" Charlemagne | Holy Roman emperor [747?-814] | Britannica.com "Charlemagne | Holy Roman emperor [747?-814]" Charlemagne | Holy Roman emperor [747?-814] | Britannica.com