The powerful patricius and magister militum of the West Aëtius is now at the height of his power.

The enmity between Aetius and Petronius Maximus, prefect of Rome in 420 and twice consul, clearly leads to the events that will gradually bring down the Western Roman Empire.

Initially however, the principal beneficiary of this will be Maximus, who, according to the historian John of Antioch, poisoned the mind of the Emperor against Aëtius, resulting in the murder of his rival at the hands of Valentinian III.

John’s account has it that Valentinian and Maximus placed a wager on a game that Maximus ended up losing.

As he did not have the money available, Maximus left his ring as a guarantee of his debt.

Valentinian then used the ring to summon to court Lucina, the chaste and beautiful wife of Maximus, whom Valentinian had long lusted after.

Lucina went to the court, believing she had been summoned by her husband, but instead found herself at dinner with Valentinian.

Although initially resisting his advances, the Emperor managed to wear her down and succeeded in raping her.

Returning home and meeting Maximus, she accused him of betrayal, believing that he had handed her over to the Emperor.

Although Maximus swore revenge, he was equally motivated by ambition to supplant "a detested and despicable rival," so he decided to move against Valentinian.

According to John of Antioch, Maximus was acutely aware that while Aëtius was alive he could not exact vengeance on Valentinian, so Aëtius had to be removed.

He therefore allied himself with a eunuch of Valentinian's, the primicerius sacri cubiculi Heraclius, who had long opposed the general with the hope of exercising more power over the emperor.

Although in 453 Aetius had been able to betroth his son Gaudentius to Valentinian's daughter Placidia, Valentinian feels intimidated by Aetius, who had once supported Joannes against him and who, Valentinian believes, wanted to place his son upon the imperial throne.

Maximus and Heraclius are therefore able to enlist Valentinian in a plot to assassinate Aetius.

The ancient historian Priscus of Panium reports that on September 21, 454, while Aëtius was at court in Ravenna delivering a financial account, Valentinian suddenly leaped from his seat and declared that he would no longer be the victim of Aëtius's drunken depravities.

He held Aëtius responsible for the empire's troubles and accused him of trying to steal the empire from him.

When Aëtius attempted to defend himself from the charges, Valentinian drew his sword and together with Heraclius, struck Aëtius on the head, killing him.

Later, when Valentinian boasted that he had done well in disposing of Aëtius, someone at court responded, "Whether well or not, I do not know.

But know that you have cut off your right hand with your left."

Edward Gibbon credits Sidonius Apollinaris with this famous observation.

Heraclius’s alliance with Petronius ends, however, with the death of Aëtius: when Maximus asks to be conferred the consulship and the patriciate, Heraclius advises Valentinian to refuse.

Heraclius, in fact, has advised the Emperor not to allow anyone to possess the power that Aëtius had wielded.