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.
Nero had been Emperor since 54 AD, and the ruling class had grown weary of his tyrannical reign. Although the conspiracy ended a failure, it sowed the seeds for the downfall of Nero, his suicide and the ensuing chaos of the Year of Four Emperors.
The fact that senators, soldiers, and equestrians were willing to work together outlines the widespread hatred of Nero. It seems as if only Piso and perhaps Plautius Lateranus were driven to participate for the love of Rome. Others plotters, such as Flavius Scaevinus and Lucanus became involved for personal revenge while some of the men wanted to be rid of emperors altogether and yearned for a return to the days of the Roman Republic. Apparently, Lucanus joined because Nero insulted his poetry and refused to allow it to be published.
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.
The conspiracy was almost uncovered at the very beginning due to the actions of a woman named Epicharis. Epicharis was involved with the conspiracy and was attempting to move it along faster: when Proculus, a Captain from Campania complained to Epicharis that Nero did not favor him, she informed him of the conspiracy. Proculus informed Nero of the conspiracy in order to gain the emperor´s favor back, and Epicharis was arrested. Though she denied the accusations, Epicharis was tortured brutally. While on transport to be tortured a second time, she committed suicide by strangling herself with her own girdle. Neither the method or the names of the conspirators were reveiled.
Finally, the plotters agreed to kill the emperor while he was in Rome at the games. The scene was set, but unfortunately for the conspirators, they never had the chance to carry out their plan.
On the morning that the conspirators’ plot was to be carried out, a freedman named Milichus and his wife discovered the conspiracy and reported it to Nero’s secretary, Epaphroditos. The plot collapsed as Scevinus, the man Milichus served, and Natalis, two conspirators whom Milichus accused, quickly gave up everything they knew.
Nero ordered Piso, the philosopher Seneca the Younger, his 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 rumored 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.”