Halsbandaffäre
Cagliostro was prosecuted in the Affair of the Diamond Necklace which involved Marie Antoinette and Prince Louis de Rohan, and was held in the Bastille for nine months but finally acquitted, when no evidence could be found connecting him to the affair. Nonetheless, he was banished from France by order of Louis XVI, and departed for England. There he was accused by French expatriate Theveneau de Morande of being Giuseppe Balsamo, which he denied in his published "Open Letter to the English People", forcing a retraction and apology from Morande.