The King of Poisons
Since the very earliest of times poisons have been used as a means for settling old scores, as instruments for personal advancement, as a means to execute criminals and by those who found life to be an intolerable burden. The ancient Greeks and Romans, who could seldom agree on anything, were both masters of this practice, but, of course, they selected different agents. The most commonly used toxin in Greece was the water hemlock, a plant in the carrot family not to be confused with the evergreen conifer common in New England. Plato immortalized hemlock, which is said to be the most violently poisonous plant in the North Temperate Zone, in his description of the death of Socrates.

In the rest of Europe from the time of the Roman Empire through the Middle Ages and the Renaissance, arsenic was the king of poisons. Mineral forms of arsenic were known as early as the fourth century BC, but the German scholastic Albertus Magnus is usually accredited with the discovery of the element around 1250. The first precise directions for the preparation of metallic arsenic, however, are found in the writings of Paracelsus, a physician-alchemist in the late Middle Ages who is often called the father of modern toxicology.