Throughout history, Catherine de' Medici has been considered something of a sorceress, a 16th-century French queen and banking heiress adroitly trained in the mixing of potions and capable of murder without a hint of remorse. One legend that has helped this reputation to endure is the story of Jeanne d'Albret, the Queen of Navarre.

Source: How Catherine de Medici Made Gloves Laced with Poison Fashionable