The conspiracy of Gaius Calpurnius Piso in AD 65 was a major turning point in the reign of the Roman emperor Nero (reign 54–68). The plot reflected the growing discontent among the ruling class of the Roman state with Nero’s increasingly despotic leadership, and as a result is a significant event on the road toward his eventual suicide and the chaos of the Year of the Four Emperors which followed.
Gaius Calpurnius Piso, a leading Roman statesman, benefactor of literature, and orator, intended to have Nero assassinated, and replace him as Emperor through acclamation by 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, where the Guard would acclaim him as emperor. The conspirators were said to have varying motives. Some wished to replace Nero with a better emperor; others wished to be free of emperors altogether, and to restore a purely Republican form of government. According to the Roman historian Tacitus, the ringleaders included a Praetorian tribune named Subrius Flavus, and a centurion named Sulpicius Asper, who helped Piso devise the plot.
The conspiracy was put in jeopardy by a woman named Epicharis, who divulged parts of the plan to Volusius Proculus, a fleet captain in Campania. Epicharis was involved with the conspiracy and was attempting to move it along faster. When Proculus complained to Epicharis that Nero did not favor him, she informed him of the conspiracy. Proculus informed Nero of the conspiracy and Epicharis was arrested. Though she denied the accusations, the conspiracy collapsed and Epicharis was tortured brutally. While on transport to be tortured a second time, she committed suicide by strangling herself with her own girdle.
On the morning that the conspirators’ plot was to be carried out (19 April) a freedman named Milichus and his wife discovered the conspiracy and reported it to Nero’s secretary, Epaphroditos. The plot collapsed as Flavius Scaevinus, the man Milichus served, and Natalis, a conspirator whom Milichus also accused, quickly gave up everything they knew.
Nero ordered Piso, the philosopher Seneca, Seneca’s nephew Lucan, and the satirist Petronius to commit suicide. Many others were also killed. In Plutarch’s version, one of the conspirators remarked to a condemned prisoner that all would change soon (because Nero would be dead). The prisoner reported the conversation to Nero, who had the conspirator tortured until he confessed the plot.
The ancient Roman historian, Tacitus, writes in Annals that “It was rumoured that Subrius Flavus and the centurions had decided in private conference, though not without Seneca’s knowledge, that, once Nero had been struck down by the agency of Piso, Piso should be disposed of in his turn, and the empire made over to Seneca; who would thus appear to have been chosen for the supreme power by innocent men, as a consequence of his distinguished virtues.”
- 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 Julius Vestinus Atticus.
Exiled or denigrated
Novius Priscus, Annius Pollio, Publius Glitius Gallus, Rufrius Crispinus, Verginius Flavus, Musonius Rufus, Cluvidienus Quietus, Julius Agrippa, Blitius Catulinus, Petronius Pricus, Julius Altinus, Caesennius Maximus, Caedicia.
Pardoned or acquitted
The novel by Naomi Mitchison, The Blood of the Martyrs (1939), is set in the months leading up to the failure of the conspiracy.