Locusta, Roman Assassin (Unknown – 69 CE)

Poison and Imperial Intrigue

Many centuries before the likes of Charlotte Corday, Shi Jianqiao and Mata Hari stalked their victims, a female assassin struck terror into the hearts of the wealthy and powerful citizens of Imperial Rome. 

Locusta was an assassin specialising in poison who thrived during the reign of the Emperor Nero (54-68 CE) and was instrumental in his rise to power. According to Tacitus, Suetonius and Cassius Dio, Nero and his mother Agrippina harnessed Locusta’s skills to remove Nero’s rivals for the throne. 

Locusta was an expert assassin, specialising in poison.

Locusta had enjoyed a successful career as an assassin before encountering Agrippina and Nero, but in 54 BCE had been caught and tried for murder. She would have been executed had not Agrippina intervened and requested her assistance in helping remove her husband, the Emperor Claudius, from the throne and, you know, life… 

Locusta and Agrippina conspired with the eunuch Halotus, Claudius’ food taster, to poison the emperor. Locusta’s poison was supposedly given to Claudius in a dish of mushrooms, which isn’t what we’d like for our last meal but whatever floats your boat. It’s uncertain if the poison was placed in the dish, or the mushrooms themselves were poisonous. 

But Claudius did not give up that easily! Another dose of poison had to be administered by Claudius’ doctor, turned conspirator, Xenophon. Perhaps more ingeniously than the mushrooms, the second dose was given on the end of a feather which Xenophon shoved down Claudius’ throat supposedly to help him throw up. His throat closing and unable to cry out, Claudius’ death was hardly quick or peaceful. 

Claudius died on 13th October 54 CE, leaving his teenage son Britannicus at the mercy of Agrippina and Nero, who had been declared Emperor upon Claudius’ death.

Cassius Dio (c. 155 – c. 235 CE) is one of our main sources on Locusta.

With these two fabulously foul individuals at Rome’s helm, it is not surprising that Britannicus met an unfortunate and similarly sticky end to his father. Worried that Britannicus’ claim to the throne (as Claudius’ biological son) was stronger than his own, Nero followed his mother’s suit and requested Locusta’s assistance. 

Locusta had her qualms about assassinating Britannicus and tried, unsuccessfully, to save the teenager by giving him a lower dose of poison. Nero was not fooled by her feigned attempt and flogged Locusta until she agreed to administer the fatal dose.

Britannicus died from poison on 11th February 55 CE, with Nero claiming that he had suffered an epileptic fit. Nero’s accession to the throne was secure and Locusta, along with Agrippina, had both played large parts in his success.

Pleased with Locusta’s assassination of Britannicus, Nero pardoned her and presented her with a country estate. Here, Locusta took on the role of teacher, with other assassins visiting her (supposedly on the orders of Nero) to learn her craft. 

We’d like to tell you that Locusta, having survived Nero’s reign of flamboyant murder, lived a long life, happily poisoning away. Unfortunately, her past caught up with her when Nero’s successor, Galba, took the throne in 69 BCE. Rounding up Locusta alongside Nero’s equally unpleasant henchmen, Rome’s most prolific female assassin was paraded through the streets of Rome in chains and subsequently executed.

A few things to note:

  1. Nero and those associated with him are generally not treated kindly by ancient authors (Tacitus throws some serious shade), so we should treat some of the accounts with scepticism. To what extent Nero and Agrippina relied upon Locusta’s talents is difficult to ascertain, nevertheless it is highly likely that Locusta was a successful assassin operating during the 1st century BCE, with close links to the Imperial court.
  2. Women in the ancient world were closely associated with poison, and Tacitus plays up this stereotype (cf. Barrett, 1998: 207). Such an association also led Locusta to be labelled as a sorceress or witch by Cassius Dio, as poison and witchcraft were linked in Greco-Roman culture.


Cassius Dio, Roman History: 61, 63.

Juvenal, Satires 1.70-72

Suetonius, Life of Nero: 33, 47.

Tacitus, Annals: 12.66, 13.15.

Barrett, A. 1998. Agrippina: Sex, Power and Politics in the Early Empire. New Haven: Yale University Press.

Grimm-Samuel, V. 1991. On the Mushroom That Deified the Emperor Claudius. The Classical Quarterly. Vol. 41/1, pp. 178-182.

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