It is beyond a doubt that during the sixteenth century, and the years immediately preceding and following it, poisoning had been brought to a pitch of perfection which remains unknown to modern chemistry, but which is indisputably proved by history. Italy, the cradle of modern science, was at that time, the inventor and mistress of these secrets, many of which are lost.
Honoré De Balzac (1799–1850), French novelist. (1846, trans. by George Saintsbury, 1971). About Catherine of Medici, First published in book form as Catherine de Medici expliquée, Souverain (1843), It was subsequently included in the Conte et romans philosophiques, in the Etudes philsophique, and finally in the Comédie humaine.