He was the subject of many legends in the folklore of Catherine de' Medici, and reputed as a master of the occult, black magic, and witchcraft during his lifetime.
In 1574, he became implicated in the attempted homicide of Joseph Boniface de La Môle, when he was reputedly hired to bring about the death of Charles IX by the use of sorcery.
During the queenship of Marie de' Medici, he was a personal friend of the queen's favorites Concino Concini and Leonora Dori.
When he died in Paris in 1615, riots broke out because of rumors about magicians caused by his refusal to receive sacrament on his deathbed, which was also the subject of a libel against him, denouncing him as a sorcerer.
He allegedly correctly predicted to Catherine de Medici that three of her sons would be kings, and how long they would reign, by the help of an enchanted mirror in the Chaumont-sur-Loire.