The castle museum of Mayenne takes place in a former Carolingian residence from the 10th century, one of the best preserved in Europe. Built during the reign of Charles the Simple, this historic monument has undergone many transformations over the centuries, becoming a prison in the 18th century before being bought by the city in the 1930s to be opened to the public. Dominating the Mayenne on its rocky outcrop, the castle takes place on the Marches of Brittany and was once used to defend Maine from invasions from Brittany, Normandy or Anjou.
Opened in 2008, the Mayenne castle museum now offers permanent collections on archaeological discoveries made on the site.