The evolution of the Roman Empire witnessed the Roman senators’ power diminishing during the Julio-Claudian era. The early conspiracies under Augustus posed a threat from these powerful families but did not undermine the power of the emperors. While there were other conspiracies under the early emperors, none were as serious and broad as the conspiracy of Gnaeus Calpurnius Piso. The conspiracy intended to use Piso as a figurehead and have power in the Praetorian Guard. The plot was exposed, and its members were executed. However, the plot showed that members of the household and the Praetorian Guard were becoming increasingly concerned with Emperor Nero’s reign, ultimately leading a few years later to whole-scale rebellion.
Piso was from a distinguished family. His grandfather, also named Gnaeus Calpurnius Piso, was a friend of Emperor Tiberius. The elder Piso was implicated in the death of Germanicus and committed suicide when Tiberius refused to help him at his trial. However, the family did not suffer, as Piso’s son Lucius held the consulship during Tiberius’s reign and married well. Inheriting his wealth from his mother, the daughter of Marcus Licinius Crassus Dives, Piso was known for his generosity and beneficence to all social classes. The family was connected with other great men of the republic, including Pompey. Piso was known to be tall, good-looking, and good-natured and excelled in the courts and oratory, the ideal Roman. On the other hand, he was known for being ostentatious and giving in to sensual pleasures. Emperor Caligula desired Piso’s wife, forcing her to divorce Piso, and then Caligula banished him for committing adultery with his own wife. Piso returned a year after Caligula’s assassination. Upon his return the new emperor, Claudius, made Piso his coconsul in 41, and Piso became a leading senator; later his stature increased under Nero.
During the reign of Nero, Piso was seen as one of the leading senators. In 65 CE after witnessing 11 years of Nero’s reign, Piso plotted to assassinate the emperor and have the Praetorian Guard declare him emperor. In order to achieve this, Piso enlisted the help of Faenius Rufus, cocommander of the Praetorian Guard who had close ties and affinity with Nero’s mother Agrippina, whom Nero had executed. Other individuals such as senators, guards, and officials were also brought into the plan, and each had his own motive but seemingly were united in their hatred of Nero. While Piso was the figurehead of the conspiracy, it appears that officers in the Praetorian Guard, such as the tribune Subrius Flavus and the centurion Sulpicius Asper, were the actual driving force behind the act. Flavus appears to have used Piso as the figurehead to gather support, and according to the ancient author Tacitus, Flavus assassinated Piso and handed power over to Seneca the Younger (Tacitus 1956, 15:47-74). Flavus would later state that he hated Nero for murdering Agrippina and Octavia (Nero’s wife).
The plot was not well organized, and too much information seems to have been available. One of the fleet captains, Volusius Proculus, was told of the plot by a freedwoman, Epicharis, who appears to have been involved with Seneca’s brother. She hoped that Proculus would join the plot and bring over the sailors, but he reported it to Nero, who had Epicharis tortured. She did not give up any names and committed suicide rather than continue being tortured. Finally, on April 19, 65 CE, the plot was fully uncovered when Milichus, a freedman, was urged by his wife to report the plot. It appears from Plutarch that one of the conspirators told a condemned prisoner to have hope, as all would change (i. e., Nero would be gone). The prisoner relayed this to Nero, and the conspirator was tortured, revealing the plot (Plutarch and Babbitt 1927, 505C). From the passages of Tacitus and Plutarch, it appears that the conspirators, being so many, could not ensure confidentiality and secrecy. Nero ordered the arrest of all conspirators and forced Piso to commit suicide.
Those involved included the consul Plautius Lateranus; the prefect Faenius Rufus; the senators Afranius Quintianus and Flavius Scaevinus (master of the freedman Milichus); the equestrian Anonius Natalis; Lucan, who appears to have implicated his uncle Seneca the Younger; and Epicharis. When Milichus informed on his master Scaevinus, he then betrayed others.
The result of the conspiracy being exposed led to a series of trials, resulting in 19 being put to death or forced to commit suicide and 13 being exiled. Piso of course was implicated and allowed to commit suicide. Other important individuals who were executed or allowed to commit suicide included Subrius Flavus, who was beheaded; the prefect Faenius Rufus; and Seneca the Younger, who was probably not involved in the plot but was ordered by Nero to kill himself. Lucan, Seneca’s nephew who joined the conspiracy, implicated his mother as he lay dying, but she escaped punishment.
The conspiracy allowed Tigellinus, the prefect of the Praetorian Guard, to hunt down his enemies and accuse some of being involved even if they weren’t. The conspiracy showed the deep-seated hatred of Nero that would soon manifest itself in a series of rebellions throughout the empire by several of his generals, leading ultimately to Galba being proclaimed emperor and Nero committing suicide.
The final internal crisis was the Jewish Rebellion begun in 66. The rebellion, caused by high taxes and Roman abuse, led to a full-scale war; Nero dispatched Vespasian and his army from Syria to quell the rebellion. After initial setbacks the Romans were successful in taking and destroying Jerusalem, but only after Nero’s death.
In 68 a rebellion broke out in Gaul. Nero ordered the army from Germany to stamp out the rebellion, while Galba was called upon by the rebels to seize power. Although the rebellion was put down, Galba was soon hailed emperor and urged to march on Rome. When the commander of the Praetorian Guard came out in favor of Galba, Nero fled, only to be forced to return after not finding troops loyal to him. When he realized that he was abandoned, he fled the city again, arriving at a freedman’s villa. He received news that the Senate had declared him a public enemy, not true, but believing that it would kill him he decided to commit suicide but could not bring himself to do the deed; he pleaded with his secretary to kill him. When the Senate heard of his death it did declare him a public enemy to win favor with Galba, whom it had previously declared a public enemy.
While most looked to Galba as someone who would restore the sanity of the empire, they were soon disappointed. Marching from Spain to Rome with his legion, Galba exacted enormous fines from cities that did not receive him quickly. He also rescinded many of Nero’s reforms including those that benefited individuals and regions from not paying taxes. Galba also refused to grant citizenship to many who asked, since this would allow the recipient to not pay taxes. When he arrived in Rome, Galba refused to pay the Praetorian Guard its bonus, which it had been promised. He also dismissed the Batavian (German) bodyguard. Because Vindex had been defeated by the German governor and his troops, Galba did not trust them and replaced the governor with Aulus Vitellius.
On January 1, 69, the German legions did not swear allegiance to the emperor as was customary with the start of the new year. The next day they proclaimed Aulus Vitellius their emperor. When Galba heard that the Rhine legions had deserted him, on January 10 he proclaimed Lucius Calpurnius Piso Frugi Licinianus his successor in hopes of rallying support from the upper echelons of society, since he was a descendant from both Pompey and Crassus, the triumvirs in the late republic. Marcus Salvius Otho meanwhile had been proposed as heir and was upset that he did not receive it. Galba passed him over, since he was a favorite of Nero and was known for his lack of morals. Outraged, Otho decided that both men needed to be removed and raised a rebellion. Both Galba and Licinianus were butchered in the Forum by the Praetorian Guard; supposedly 120 soldiers claimed responsibility in hopes of getting a reward. Otho wrote their names down, which was disastrous for them.
On January 15, Otho went to Palatine Hill and was hailed emperor by the Praetorian Guard, whereupon he and his forces moved against Galba and killed him. Otho was then proclaimed emperor by the Senate that very same day. Whereas Galba had not paid the Praetorian Guard its gold and the populace of Rome had still revered Nero, Otho immediately played into both camps.
In 69 CE the Roman Empire convulsed with a civil war, the Year of the Four Emperors. Nero had committed suicide in 68, and the new emperor, Galba, the governor of Spain, marched on Rome. During the year 69 four men would rule the empire, with the last, Vespasian, winning and surviving. On July 1 Vespasian was in Alexandria, Egypt, while Titus continued operations in Judea against the Jews. In Alexandria, Vespasian was in control of the grain supply going to Rome and was proclaimed emperor by the governor of Egypt. The troops in Judea followed suit, and Vespasian began his journey to Rome. By the end of the year he was emperor.
Further Reading Griffin, Miriam T. 1985. Nero: The End of a Dynasty. New Haven, CT: Yale University Press. Pagan, Victoria Emma. 2004. Conspiracy Narratives in Roman History. Austin: University of Texas Press. Plutarch and Frank Cole Babbitt. 1927. Plutarch’s Moralia. London: W. Heinemann. Tacitus, Cornelius. 1956. The Annals of Imperial Rome. Translated by Michael Grant. Baltimore: Penguin.