Mamertines

The Mamertines (Mamertini "sons of Mars") were mercenaries of Italian origin who had been hired from their home in Campania by Agathocles (361 – 289 BC), Tyrant of Syracuse and self-proclaimed King of Sicily. After Syracuse lost the Third Sicilian War, the city of Messana was ceded to Carthage in 307 BC. When Agathocles died in 289 BC he left many of his mercenaries idle and unemployed in Sicily. Most of them returned home but some liking the climate and the prospect of adventure on a foreign island remained. They played a major role in the lead up to the First Punic War.

In 280 BC, the Syracusans appealed to King Pyrrhus of Epirus for help against the Mamertines.

The then-small band of desperados came across the walled Greek settlement of Messana (now Messina). Messana was built on a strategic location on the north-eastern tip of Sicily on the strait between Sicily and Italy. Together with the fort Rhegium on the toe of Italy, it was the crossing point between Italy and Sicily. Being a peaceful people, the inhabitants allowed the travelling mercenaries into their homes. After a time, the mercenaries became restless and plotted to capture the town. One night, the mercenaries betrayed their hosts and killed most of the population, who were unprepared. In this way, they claimed Messana for themselves. The surviving Messanians were thrown out and the property and women divided. After their victory, the mercenaries named themselves the Mamertines after the Oscan war-god Mamers.

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Wikipedia