The Pisonian Conspiracy: The ancient Roman plot to overthrow Nero that almost succeeded

Nero Claudius Caesar Augustus Germanicus became emperor in AD 54, after the death of his adoptive father, the Emperor Claudius.

At the start of his reign, he had relied on the guidance of his mother, Agrippina the Younger, the philosopher Seneca, and the praetorian prefect Burrus.

Over time, he had largely dismissed their influence and had begun to rule according to his own desires, which increasingly offended the Roman elite. 

Eventually, many senators and aristocrats grew angry at his rejection of traditional values.

Instead of promoting military service and civic duty together with restraint, Nero took the stage as a performer, competed in public games, and surrounded himself with actors, singers, and dancers.

He used imperial funds for lavish projects rather than the needs of the empire. He also removed advisors who disagreed with him and treated the Senate with open contempt. 

After the Great Fire of Rome in AD 64, public anger increased because many Romans publicly believed that Nero had either caused the fire or had failed to stop it.

To shift blame, he accused the Christian community and used the charge to justify a wave of executions that involved public torture and executions staged as spectacles, which led many Romans, even those with no sympathy for Christians, to view the response as excessive and cruel.

At the same time, his decision to construct the sprawling Domus Aurea on land cleared by the fire heightened suspicions and reinforced his image as a ruler who cared more for luxury than duty. 

Nero’s family murders reinforced the view that no one remained safe because he had ordered his mother’s death in AD 59, had killed his wife Octavia in AD 62, and had treated executions as a matter of convenience.

Among the ruling class, fear spread quickly. Quiet conversations turned toward the idea of rebellion, since few believed that the emperor would change or tolerate dissent.

Prior tensions had surfaced around figures such as Rubellius Plautus and Faustus Cornelius Sulla, both of whom were executed under suspicion of posing dynastic threats, though no formal conspiracies had been confirmed at the time. 

The central figure in the plot was Gaius Calpurnius Piso, a nobleman with ancient lineage who had served as consul in AD 57.

His ancestry traced back to the respected Calpurnii Pisones, a family with a long history of consular rank.

Well known for his generosity and oratory skill, Piso gained support among senators and equestrians who wanted an alternative to Nero, since he offered no radical reform.

Many believed he could restore a dignified, stable imperial leadership with renewed honour.

Tacitus noted that Piso was popular, but he also had a reputation for self-indulgence and unrestrained behaviour that his enemies used to question his motives. 

Importantly, Piso did not act alone. The conspiracy grew into a broad alliance that included civilians and military personnel.

Subrius Flavus was a praetorian tribune and Sulpicius Asper was a centurion, and they offered to carry out the assassination directly.

Later reports suggest that Subrius Flavus preferred Seneca as a candidate for emperor, which would suggest some disagreements existed even among the conspirators. 

Other conspirators included Plautius Lateranus, a senator who agreed to strike the fatal blow, and Epicharis, a freedwoman who attempted to recruit naval officers stationed at Misenum.

Her unauthorised actions clearly demonstrated how far dissatisfaction with Nero had spread.

Although Seneca’s involvement remains unclear, his connection to Piso and the political circles that surrounded the conspiracy drew immediate suspicion once names began to surface. 

Each new supporter gave the plot somewhat greater strength. However, each new name also added significant risk, since secrecy became harder to maintain as the group expanded.

Ancient sources suggest that as many as 41 individuals were formally accused, and dozens more may have been involved or implicated. 

The conspirators agreed that they needed to strike Nero in a setting where he would feel secure and unguarded.

One plan involved murdering him at a public performance in the Circus, where assassins could hide in the crowd and escape during the confusion.

Piso would then present himself as the new emperor and seek to appeal to the people and the Guard for support. 

Some conspirators favoured a more private setting, such as during musical recitals, when Nero often insisted on silence and dismissed his personal guards.

A well-placed attacker could strike without warning. Others suggested ambushing him on the road, since his travel parties often lacked full protection.

All options depended on acting quickly, controlling the message, and securing the support of the military before resistance could form. 

To prepare, Piso used his social connections to approach likely allies. He made promises of advancement, political favour, and shared authority to those who would back his claim once Nero had been removed.

The group understood that they had only one chance. Once they began, any hesitation or error would expose them all.

The conspiracy began to unravel when Epicharis attempted to recruit naval officers by promising that powerful men in Rome had already committed to action, and she approached Volusius Proculus, a fleet captain, and urged him to join.

However, soon after, he reported her to the authorities, and interrogators tortured her, yet she refused to speak, and the authorities detained her and planned further questioning.

Before that could happen, Epicharis used the cords from her prison cell to strangle herself and she chose death over betrayal. 

The next development came from an unexpected source. Milichus was a freedman in the household of the senator Flavius Scaevinus, and he overheard his master, who was sharpening a dagger and gathering bandages, and this made him suspect that violence was imminent.

So, he went to Nero’s agents and exposed what he had seen. Some conspirators confessed to save themselves, while others denied involvement until they faced torture.

The chain of confessions moved swiftly from equestrians to senators and reached members of the Praetorian Guard. 

Soon, the entire structure of the conspiracy collapsed, and those who had plotted for months scrambled frantically to save their lives, since Nero had no interest in leniency. 

Piso, who was once the hope of many senators, had received orders to take his own life, and he obeyed without protest.

Lucan, who died by the same method, recited lines of his poetry during his final moments, and Seneca, whose political silence had not saved him, opened his veins, took poison, and then entered a warm bath.

His wife Paulina tried to join him but guards intervened and forced her to live. 

Some conspirators were executed publicly, and others were allowed to choose suicide, and the message became unmistakably clear that anyone who challenged Nero would die and anyone who stayed silent might survive but would never feel secure again. 

Nero used the exposure of the conspiracy to strengthen his power. The Senate declared its loyalty, issued honours to the emperor, and praised his supposed wisdom in discovering the plot, so no one dared question the trials or the sentences.

Many withdrew from public life. They avoided political gatherings and refused to speak openly in case someone listened. 

Tacitus later described the events in detail in Book 15 of his Annals, and he believed the failure of the conspiracy led to even greater repression.

Suetonius and Cassius Dio also recorded versions of the events, though with different emphases.

Nero no longer restrained himself, as he now punished minor offences and expanded his network of spies and informers.

The Pisonian Conspiracy, which once promised a return to order, gave Nero the excuse to destroy his remaining critics, and he ruled without significant opposition until AD 68, when rebellion finally forced him to flee and kill himself.