The edifice is comprised of two distinct sections: an austere 14C keep** that has retained its original crenellated walls and machicolations, and a majestic 17C structure with a royal courtyard and chapel*. The ground-floor of the keep was formerly the site of the kitchens and the two upper storeys housed the apartments of the king of France. In the 16C the castle became a state prison. It was essentially used to incarcerate political prisoners: the Grand Condé, Prince of Conti, Cardinal of Retz, Diderot, Mirabeau, etc, among others. It was here that by order of Louis XIV, D'Artagnan mounted guard over Fouquet, arrested in 1662.