Fronsac's mound owes its history to its privileged position. It was the site of the Gauls' market, the Romans erected an altar there, and Charlemagne built a fortified camp on the mound ("Franciacus") in 769, where the Basques led by duke Lupo came to pledge allegiance to the Frankish King after Aquitaine's submission. In 849, Fronsac was pillaged by Hasting, the chief of the Vikings. The Marechal of Richelieu had a "folly" built there, to an extravagant architectural design, where he held courtly entertainments. As word spread of these events, the renown of Fronsac's wines was carried with it to the Court of Versailles. In the 18th Century, the names of Fronsac and Canon Fronsac enjoyed a very good reputation. It was at this time that the concept of "cru" first appeared in the Libournais.