Wikipedia
Einhard
Einhard (also Eginhard or Einhart; ; 775 – March 14, 840 AD) was a Frankish scholar and courtier. Einhard was a dedicated servant of Charlemagne and his son Louis the Pious; his main work is a biography of Charlemagne, the Vita Karoli Magni, "one of the most precious literary bequests of the early Middle Ages."