The Assassination of Pertinax marks the violent failure of a ruler who tried to govern the Roman Empire through discipline and justice after the permissive reign of Commodus. In the political logic of the narrative, Pertinax’s death is not merely a change of emperor: it exposes the danger of confronting a powerful military faction without first securing its loyalty, and it supplies Septimius Severus with the public cause behind which he conceals his bid for the Empire.

Causes and Political Background

Pertinax was chosen Emperor against the will of the soldiery. The troops had grown accustomed to the licentious life permitted under Commodus, whereas Pertinax attempted to restore stricter discipline. His reform therefore threatened the habits and privileges of the very force on which a new emperor needed to depend. The conflict was structural as well as personal: the emperor represented restraint, while the soldiers had come to expect indulgence.

The narrative also stresses that a ruler may incur hatred through good actions as well as bad ones. Pertinax’s effort to correct military disorder was presented as responsible government, but virtue became politically dangerous because the soldiers were not prepared to accept it. A prince who relies on a corrupt class must adapt himself to that class’s humors or risk losing the support on which his authority rests.

The Assassination

The soldiers’ hostility quickly became decisive. Pertinax made himself hated by imposing the discipline they resisted, and his advanced age caused him to be despised as well. He was therefore ruined at the very outset of his reign. The account treats the killing as the culmination of a failed relationship between emperor and army rather than as an isolated act of personal violence: the soldiery rejected the ruler’s standards and removed him before he could consolidate power.

The assassination also confirms the broader contrast between Pertinax and Marcus Aurelius. Marcus, though temperate, just, and opposed to cruelty, had inherited the Empire and possessed virtues that kept both the people and the soldiers within bounds. Pertinax did not enjoy the same secure foundation. His attempt to impose order came after the army had been shaped by Commodus, and the Guard’s resistance turned reform into a fatal political liability.

Septimius Severus and the Exploitation of the Death

Pertinax’s death immediately became the central pretext for Septimius Severus. Commanding the army in Illyria, Severus persuaded his troops that they had a duty to march to Rome to avenge the murdered emperor. He did not disclose his intention to claim the Empire; instead, he presented the expedition as an act of retribution. This concealment allowed him to transform military ambition into an apparently legitimate response to the assassination.

Severus moved before the authorities in Rome understood what was happening. His army reached Italy before his departure was known, and the Senate, acting from fear, elected him Emperor. Julianus was then put to death. The sequence reveals how Pertinax’s murder destabilized the succession: the killing removed one ruler, created a vacuum, and furnished the next claimant with both a moral justification and a practical route into Rome.

Consequences and Imperial Consolidation

Severus still faced two rivals after securing Rome. Niger, commanding the armies of the East, had proclaimed himself Emperor in Asia, while Albinus held power in the West and also aspired to the imperial dignity. Severus judged it dangerous to fight both openly. He therefore opposed Niger by arms and Albinus by deception, sending Albinus the title of Caesar and claiming that he wished to share the imperial dignity with him.

Once Severus had defeated and slain Niger and restored tranquillity in the East, he returned to Rome and accused Albinus of treacherously seeking his destruction. He then marched against him in Gaul, stripped him of his dignities, and killed him. The assassination of Pertinax thus initiated a chain of succession struggles that ended not in a stable settlement but in Severus’s violent monopoly of imperial power.

Narrative and Political Significance

The event demonstrates the instability of a principality whose ruler cannot command the armed force that sustains him. Pertinax’s personal qualities did not protect him because the army’s expectations were stronger than his authority. His death also shows why the narrative distinguishes between moral virtue and political effectiveness: justice and restraint may be admirable, yet they can destroy a ruler when imposed upon a faction that profits from disorder.

For Severus, the assassination becomes the occasion to combine the lion and the fox. He uses the lion’s force in his campaigns against Niger and Albinus, but the fox’s craft in concealing his design from the troops and deceiving Albinus. The dead Pertinax remains the public justification for this movement, while the actual consequence is the rise of a new emperor who maintains power through fear, military loyalty, calculation, and reputation.