As early as the Bronze Age, the mineral arsenic was added to bronze to make it harder, although isolating it chemically and understanding it as an element was not recorded until 815CE by Jābir ibn Hayyān. Albertus Magnus (pictured) isolated the element arsenic from arsenic trisulfide by heating it with soap in 1250.
Non-pure forms of arsenic were known much earlier. Dioscorides during Nero's reign described arsenic as a poison in the 1st century, noting its odorless and tasteless and colorless properties, making it ideal to mix with food or drink. Arsenic poisoning's side effects were similar to food poisoning, so immediate detection was unlikely. A sufficiently large dose, however, produced violent cramping, diarrhea, vomiting, and death.
You could also use smaller doses on a victim over time, leading to headaches, mental and physical fatigue, confusion, hair loss, and paralysis. The preferred form of arsenic was white arsenic, arsenic trioxide, whose fatal dose was the size of a pea.
Arsenic compounds exist everywhere: in groundwater and (as a result) in trace amounts in plants. Organic arsenic compounds can be found in low levels in seafood. Lettuce, kale, mustard, and turnip greens store arsenic in their leaves. Beets, turnips, carrots radishes, and potatoes store arsenic mostly in their skins. There is also arsenic in the plants of tomatoes, peppers, squash, cucumbers, peas, beans, corn, melons, and strawberries, but not the parts that we eat. (Apple seeds contain. cyanide, but that's another story.)
The Borgias of Italy—including Rodrigo Lanzol Borgia, who became Pope Alexander VI in 1492, and his son Cesare and daughter Lucrezia—were known for their use of arsenic for political and financial advancement. They would take advantage of legal loopholes to appropriate the estates of certain men after killing them with arsenic-laced wine.
In fact, poisoning became so common that Italian court documents show plenty of cases in which we find the details of the poisoning:
The poisoner made appointments and had set prices, the client named the victim and a contract was made, and the poisoner was paid when the job was done. [link]
There was also a woman named Giulia Toffana around this time who made arsenic-laced cosmetics, so the victims could be induced to poison themselves.
If you suspected you had been poisoned, what would you do? Probably go to an apothecary to buy a cure. We'll talk about medieval apothecaries next time.
