J. Collin de Plancy was born in France in 1793. He became a "freethinker" influenced by Voltaire. He was a printer-librarian in Plancy and Paris. In 1839, in Holland, he founded The Hague Society of Fine Arts. It was during his stay in the Netherlands that he was reconciled with God and the Catholic faith. In 1841, he made his conversion public, declaring that he condemned and trampled underfoot all that he had written against faith and morals. All his works would henceforth display ecclesiastical approval. His most important work is considered the Dictionnaire Infernal, in which he gathered all the knowledge of the time concerning superstitions and demonology. It underwent six editions while Plancy was alive. The first edition was published in 1818; the third edition, published in 1844, was re-worked to be in accordance with the Church, and features the approbation of the Archbishop of Paris.
