The conspiracy of Gaius Calpurnius Piso in AD 65 was a major turning point in the reign of the Roman emperor Nero (54–68). The plot reflected the growing discontent among the upper social strata of the Roman state with Nero's increasingly despotic leadership, and as a result is a significant event on the road towards his eventual suicide, and the chaos that followed.
Gaius Calpurnius Piso, a renowned Roman statesman, literary benefactor, and orator, intended to have Nero assassinated with the goal of having himself declared Emperor of Rome by the imperial bodyguard, known as the Praetorian Guard. He enlisted the aid of several prominent senators, equestrians, and soldiers with a loosely conceived plan in which Faenius Rufus—joint prefect of the Praetorian Guard with Ofonius Tigellinus—would conduct Piso to the Praetorian Camp for a formal declaration by the Guard. The conspirators were said to have varying motives: some were imperialists and others were pro-republic. According to the ancient historian Tacitus, the ringleaders included Subrius Flavus, a tribune of the Praetorian court, and the centurion Sulpicius Asper, who helped Piso spawn the scheme.
The conspiracy was almost betrayed by a woman named Epicharis, who divulged parts of the plan to Volusius Proculus, a fleet captain in Campania. When Proculus complained to Epicharis that Nero did not favor him, she revealed the plot without giving him names. Instead of joining the conspiracy as Epicharis thought he would, Proculus instead turned her in. Under torture, she revealed details and names, but she remained loyal to the conspiracy and did not betray it.
Tacitus, the main source on the events of the conspiracy, admits to lacking knowledge about how Epicharis originally gained knowledge of the conspiracy. He says in his work Annales: "Meanwhile, as they were delaying and deferring hope and fear, a certain Epicharis provoked and blamed the conspirators; it is uncertain how she became actively informed".
The freedman Milichus later discovered the conspiracy on April 19, AD 65, and reported it to Nero's secretary, Epaphroditos, after his wife persuaded him to do so. After the conspiracy was revealed, Nero ordered Piso and its leaders to commit suicide. The philosopher Seneca, the poet Marcus Annaeus Lucanus, and the satirist Petronius were also implicated in the plot and dealt with in a similar fashion. A relevant, little known passage, Plutarch Moralia 505C, has been identified, which adds a story not told in Tacitus: A conspirator, in passing a condemned prisoner, urged him to have hope, dropping a comment that indicated that all would change soon (because Nero would be dead). Instead of silently taking heart, the prisoner revealed the conversation to Nero, the conspirator was tortured, and the plot was betrayed.
Piso's brother, Lucius Calpurnius Piso Licinianus, was adopted by Galba in January AD 69, a move that cost both Galba and Piso their lives and pushed Rome into the upheaval known as the Year of Four Emperors. Earlier members of the family enjoyed close ties to Julius Caesar, Augustus, and Tiberius. The family fell out of favor during the reigns of Caligula and Claudius. The Piso brothers' parents were implicated in a charge of treason and forced to commit suicide.
- See also Members of the Pisonian conspiracy
At least 41 individuals were accused of being part of the conspiracy. Of the known 41, there were 19 Senators, 7 Equites, 11 soldiers and 4 women.
Executed or forced to commit suicide
Piso, Plautius Lateranus, Lucan, Afranius Quintianus, Flavius Scaevinus, Claudius Senecio, Vulcatius Araricus, Julius Augurinus, Munatius Gratus, Marcius Festus, Faenius Rufus, Subrius Flavus, Sulpicius Asper, Maximus Scaurus, Venetus Paulus, Epicharis, Seneca the Younger, Antonia, Marcus Vestinus Atticus.
Exiled or denigrated
Novius Priscus, Annius Pollio, Glitius Gallus, Rufrius Crispinus, Verginius Flavus, Musonius Rufus, Cluvidienus Quietus, Julius Agrippa, Blitius Catulinus, Petronius Pricus, Julius Altinus, Caesennius Maximus, Caedicia, Pompeius, Cornelius Martialis, Flavius Nepos, Statius Domitius
Pardoned or acquitted
Antonius Natalis, Cervarius Proculus, Statius Proximus, Gavius Silvanus, Acilia
- Pagán, Victoria Emma. Conspiracy Narratives in Roman History. Austin, TX: University of Texas Press, 2004. Pp. ix + 197. ISBN 0-292-70561-1.