Mithridates was Rome’s most dangerous foreign enemy in the 1st century b.c. He arranged for the massacre of perhaps more than a hundred thousand Roman officials and merchants, along with their families, in Asia Minor (now Turkey) in a single day.
When Mithridates was a baby, lightning burned his clothing but left him unscathed, except for a scar on his forehead hidden under his hair ( Plutarch Table-Talk 1.6).
It is well known that Mithridates is the only person who has ever spoken twenty-two languages. Throughout his reign of fifty-six years, he never spoke through an interpreter to any of his subjects (Pliny Natural History 25.6). Frederick II ( stupor mundi , “The Wonder of the World”), who ruled the Holy Roman Empire from 1220 to 1250, could speak a mere nine languages.
When he defeated Mithridates, Pompey discovered in his personal notebook a recipe for an antidote to poisons: two dried walnuts and two figs ground up with twenty leaves of rue and a pinch of salt. Taking this on an empty stomach safeguards a person against poison for a whole day (Pliny Natural History 23.149). Pliny elsewhere credits Mithridates with a much more elaborate universal antidote to poison, concocted with fifty-four ingredients (29.24). Celsus records a detailed and complex version of the recipe ( On Medicine 5.23).
When his long reign finally came to its close, Mithridates lamented that he had found no antidote to the deadliest of all poisons, one which infects every royal house, the treachery of soldiers, children, and friends. He attempted suicide by poison but failed, because of the immunity which he had developed through taking small doses regularly (Appian The Wars against Mithridates 16.111). In Italian and Romanian, the verbs mitridatizare and a mitridatiza are still used to refer to administering an antidote to poison.
Mithridates also took measures against other forms of assassination. He had little confidence in armed guards to protect him while he slept, so he had a bull, a horse, and a stag trained to watch over him. If anyone approached him while he was asleep, these animals would immediately detect the intruder by sensing his breathing and wake Mithridates, the bull by bellowing, the horse by neighing, the stag by bleating (Aelian On Animals 7.46).