The Medici Archives

One of the many arts cultivated in Renaissance Italy was the black art of poisoning. The Medici Granducal Archives are teeming with references to this nefarious branch of chemistry, including a series of documents confirming Grand Duke Cosimo I de' Medici's involvement in a plot to assassinate Piero Strozzi by means of poisoned food or drink in 1548. In February of that year, an anonymous tipster writing in cipher to Cosimo pointed out that ‘P St usually stops to drink a few times during his journey,' and explained that all that was needed was ‘an excellent toxin that could simply be put in his drinking flask.' A 1563 inventory of Cosimo's personal archive implicates him further in such sordid affairs: it shows that he kept a recipe for a deadly poison among his important private papers.

Cosimo's son Ferdinando, suspected by some to have poisoned his older brother Francesco in order to attain the Granducal throne in 1587, was every bit his father's son, even in this assassin's art. Damning evidence of his darker side is in a letter Ferdinando wrote to his agent in Milan in 1590: ‘A little poison is being sent to you, made just for this purpose ... the entire quantity is sufficient to poison a whole flask of wine, and don't use any less, and it is odorless, tasteless, and has extremely powerful effects as long as you mix it well with the wine...' Ferdinando also promised his agent that up to four thousand scudi would be rewarded to the person who succeeded in carrying out these instructions for murder.

As these notices suggest, poison was used to resolve political problems and heads of state were its frequent victims. Ferrante Gonzaga di Guastalla was rumored to be the target of the Farnese family's poisoning plot in 1547. Cosimo de' Medici was warned in 1559 that anything he might eat or drink could have deadly consequences. Felipe II, King of Spain, received the horrifying news in 1568 that his own son, Don Carlos, had attempted to poison him and his third wife, Queen Elizabeth de Valois. The very same year, the King of France died and widespread rumors posited poisoning. Queen Elizabeth I in 1586 narrowly escaped a poisoning plot hatched by her lady-in-waiting. In 1603, the cook and head waiter at the court of Henry IV of France plotted to taint the food of both the king and his consort, Maria de' Medici. When Queen Margarete von Habsburg, consort of King Felipe III, died at the Escorial in 1611, the profuse bleeding from all orifices of her head and her horridly deformed corpse cast suspicions of poisoning on her pharmacist and doctor. Clearly, there were enough poisons circulating in the courts of early modern Europe to make every king and queen shiver with dread at the slightest aching stomach or perception of an unusual taste.

The Medici Archives record the scare experienced by the powerful minister of Spain, Gaspar de Guzmán, Duke of Olivares, when dining in Valencia. ‘Having taken his first drink and tasting a very unnatural flavor in the wine, he feared poisoning jumped away from the table in a great fury asking for remedies...Meanwhile the wine steward, having heard what was going on, reassured His Excellency that the bad taste resulted from his not having rinsed the wine flask well after washing it with vinegar and salt, and when the steward then preceded to drink the same wine, finally calmed down.' Amidst such rampant fear, we can understand why some rulers reacted with vengeance upon discovering poisons in their midst, as in the case of Alfonso d'Avalos, who had his servant drawn and quartered in 1542 for merely having a poison in his possession.

While rulers were almost always in peril, it appears that no one was beyond the reach of poison in early modern Europe-not the Jewish merchant from Ferrara with a valuable diamond in his possession, who was poisoned by thieves in 1558; nor the Franciscan friars of Borgo San Sepolcro, who were killed in 1565 with the poisoned breads left at their convent by a mysterious stranger; nor the wives of two cuckholded husbands, Giangiacomo de' Medici di Marignano, and the Count of Bagno.

Wine and food were the most preferred means of delivering poison to an enemy. The Medici Archive demonstrates that other objects could also be laced with poison. Cosimo I de' Medici was warned in 1565 of a plot to poison his face towels; the Lutheran community in Seville was accused in 1561 of poisoning the wells of their Catholic neighbors; and Thomas Overbury, while imprisoned in the Tower of London, succumbed to poisons hidden in his medicine in 1615.

In light of all this poison-mongering, the question arises: what were the sources of the poisons used in the Renaissance? At least some of the poisons could be found in otherwise innocuous household items. For example, in 1568, a 14-year-old Sienese girl who poisoned her family's dinner salad in order to evade forced entrance into a convent had obtained her deadly weapon by grinding down one of the mercury glass mirrors that her mother and older sister used for primping. Other poisons were the result of scientific research by botanical experts. A ‘liquor of venomous plants for killing large animals' was prepared in Madrid at the request of Francesco de' Medici in 1575 by the Duke of Alva's herbalist. Along with the poison, the Duke of Alva also sent Francesco special crossbow arrows that could deliver the poison under the victim's skin. The note that the Duke of Alva sent with the package of poison explained that his herbalist ‘had never made such a good batch, which is why it has taken so long to arrive.' Ironically, the Duke of Alva also included in his note a request for a refill of the Medici's anti-poison oil, since his wife had finished off their supply.

Though usually poisoning was done for evil purposes, some deliberate poisonings did not constitute legal murder, such as those that were designed to test the efficacy of poison remedies. These dangerous experiments, which involved giving the test subject a poison followed by the supposed antidote, were carried out on animals like chickens and dogs, as well as humans awaiting capital punishment. In 1546, the antidotal potency of a unicorn horn was tested successfully on a dog. Two years later, Cosimo I de' Medici sent Ferrante Gonzaga two vials from an untested batch of the famous anti-poison oil produced in the Medici pharmacy,  recommending that Gonzaga first test it out on a prisoner with a death sentence. Occasionally the test subjects participated with full consent, as in 1660, when a renegade Roman priest gained a following by performing ‘miraculous' cures, which in truth were caused by administering poisons and their cures-both brewed up by a local woman known as Poisonous Girolama-to his collaborating servant in carefully choreographed spectacles.