What happened 268 AD

In the years 267–269, Goths and other barbarians invaded the empire in great numbers. Sources are extremely confused on the dating of these invasions, the participants, and their targets. Modern historians are not even able to discern with certainty whether there were two or more of these invasions or a single prolonged one. It seems that, at first, a major naval expedition was led by the Heruli starting from north of the Black Sea and leading to the ravaging of many cities of Greece (among them, Athens and Sparta). Then another, even more numerous army of invaders started a second naval invasion of the empire. The Romans defeated the barbarians on sea first. Gallienus' army then won a battle in Thrace, and the emperor pursued the invaders. According to some historians, he was the leader of the army who won the great Battle of Naissus, while the majority believes that the victory must be attributed to his successor, Claudius II.

In 268, at some time before or soon after the battle of Naissus, the authority of Gallienus was challenged by Aureolus, commander of the cavalry stationed in Mediolanum (Milan), who was supposed to keep an eye on Postumus. Instead, he acted as deputy to Postumus until the very last days of his revolt, when he seems to have claimed the throne for himself. The decisive battle took place at what is now Pontirolo Nuovo near Milan; Aureolus was clearly defeated and driven back to Milan. Gallienus laid siege to the city but was murdered during the siege. There are differing accounts of the murder, but the sources agree that most of Gallienus' officials wanted him dead.

Cecropius, commander of the Dalmatians, spread the word that the forces of Aureolus were leaving the city, and Gallienus left his tent without his bodyguard, only to be struck down by Cecropius. According to Aurelius Victor and Zonaras, on hearing the news that Gallienus was dead, the Senate in Rome ordered the execution of his family (including his brother Valerianus and son Marinianus) and their supporters, just before receiving a message from Claudius to spare their lives and deify his predecessor.

Whichever story is true, Gallienus was killed in the summer of 268, and Claudius was chosen by the army outside of Milan to succeed him. Accounts tell of people hearing the news of the new emperor and reacting by murdering Gallienus' family members until Claudius declared he would respect the memory of his predecessor. Claudius had the deceased emperor deified and buried in a family tomb on the Appian Way. The traitor Aureolus was not treated with the same reverence, as he was killed by his besiegers after a failed attempt to surrender.