March 16
Western Roman Emperor Valentinian III Assassinated
Two Scythian bodyguards of the murdered general Flavius Aetius struck down Emperor Valentinian III during archery practice on the Campus Martius, ending his 30-year reign amid deepening imperial instability.
Summary
In the mid-fifth century, the Western Roman Empire faced relentless pressures from barbarian invasions and internal power struggles. Flavius Aetius, the powerful magister militium who had defeated Attila the Hun at the Battle of the Catalaunian Plains in 451, dominated court politics under Emperor Valentinian III. After Valentinian murdered Aetius in September 454 amid suspicions of disloyalty, two of Aetius's Scythian bodyguards, Optelas and Thraustelas, plotted revenge with backing from senator Petronius Maximus. On March 16, 455, while Valentinian practiced archery on the Campus Martius in Rome, the assassins struck, killing the emperor and his chamberlain Heraclius. The immediate result was chaos, with Petronius Maximus briefly seizing the throne before his own demise weeks later during the Vandal sack of Rome.
Context
By the mid-fifth century the Western Roman Empire had lost effective control over much of its former territory. Vandal forces had seized North Africa in the 430s, while Hunnic raids under Attila threatened Gaul and Italy. Real power rested with military commanders rather than the imperial court in Ravenna or Rome. Flavius Aetius emerged as the dominant figure after years of civil and frontier warfare, culminating in his victory over Attila at the Catalaunian Plains in 451.
What Happened
Valentinian III, who had reigned since 425 but exercised little personal authority, grew suspicious of Aetius’s influence. On 21 September 454 he murdered the general inside the imperial palace in Rome with the aid of his chamberlain Heraclius. The following spring two of Aetius’s Scythian retainers, Optila and Thraustila, resolved to avenge their patron. Petronius Maximus, a senator nursing his own grievances, encouraged the plot. On 16 March 455 Valentinian rode out to the Campus Martius in Rome to practice archery. As he dismounted, Optila delivered a fatal blow to the emperor’s head while Thraustila simultaneously killed Heraclius. No guards intervened.
Aftermath
The assassination left no clear successor and triggered immediate political turmoil. Petronius Maximus briefly claimed the throne with senatorial backing, yet his regime collapsed within weeks. In June 455 a Vandal fleet under Gaiseric sacked Rome, and Maximus was killed while attempting to flee. The Western court entered a period of rapid, unstable successions that further eroded central authority.
Legacy
Valentinian’s death removed the last emperor who could still claim a direct link to the Theodosian dynasty and accelerated the fragmentation of the Western provinces into barbarian kingdoms. Historians view the event as emblematic of the empire’s structural weakness: emperors dependent on powerful generals yet vulnerable to their factions. The pattern of short-lived rulers continued until the deposition of Romulus Augustulus in 476.
Why It Matters
Valentinian's death accelerated the collapse of centralized authority in the Western Roman Empire, paving the way for barbarian kingdoms in Italy and beyond. It underscored the vulnerability of emperors to military factions and court intrigue, a pattern that defined the empire's final decades. The event contributed to the rapid succession of short-lived rulers and the eventual deposition of the last Western emperor, Romulus Augustulus, in 476.
Related Questions
Why did Valentinian III kill Aetius?
The emperor acted on suspicions of disloyalty fueled by court rivals, despite Aetius having preserved the empire against major invasions.
Who were the assassins of Valentinian III?
Two Scythian bodyguards named Optila and Thraustila, acting with encouragement from senator Petronius Maximus.
What happened immediately after the assassination?
Petronius Maximus briefly took the throne but was killed weeks later during the Vandal sack of Rome.
How did Valentinian’s death affect the Western Roman Empire?
It removed the last emperor with ties to the Theodosian dynasty and hastened the loss of centralized control, leading to further short-lived rulers until 476.
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Sources
- Valentinian III, Encyclopædia Britannica. Accessed 2026-07-09.