The First Punic War is often neglected in favor of its more famous successor. However, the First Punic War demonstrated the limited space of the western Mediterranean regarding the spheres of influence of the established Carthaginian Empire and the growing power of the Roman Republic. The twenty-three year conflict witnessed the first time Roman legions left the shores of the Italian Peninsula. It also was the catalyst for the construction of a reputable Roman fleet that would last for years to come. The bad blood sown from the results of the war would also yield the fruits of the Second Punic War a mere generation later.
To begin a study of the First Punic War we must look at the Mamertines. After the tyrant of Syracuse Agathocles died in 289 BC, the majority of his mercenaries became unemployed. Some bands dispersed but the Mamertines attempted to stay in Syracuse. Hailing from Campania (a region in southern Italy), perhaps related to the Samnites, the civilized Greeks did not take kindly to a large armed mob of uncultured barbaroi loitering around the Hellenistic center of Sicily. (At this time the Romans could arguably be considered more barbarous than the Carthaginians, at least to the western Greeks.) Barred from settling in Syracuse, these mercenaries headed north until they came across the town of Messana on the north-east tip of Sicily.
The town of Messana had already had a rough history in the past, but nothing had been as treacherous as what was to occur. The city offered its hospitality to the band of mercenaries and in return the mercenaries slaughtered many of the men and leading figures of the city and claimed it for themselves. “After being admitted as friends and occupying the city, they first expelled or massacred the citizens.” (Polybius 1.7)1
The women and possessions were split among the mercenaries as their own. It was at this time that the mercenaries seem to officially proclaim themselves as the Mamertines as they began to mint their own coinage. The name Mamertines means the sons of Mamers, Mamers being an Italic war god with the Latin equivalent of Mars. (I suppose the Martians did not seem as tough or assertive as the Mamertines.)
Soon afterwards, the Italian town of Rhegium suffered a similar fate. This time (when some of the Greco-Italian cities were throwing their lot with Pyrrhus in the Pyrrhic War) the Mamertines aided the rebellious Roman garrison (likely largely ethnically related to the Mamertines) in taking over the town. The commander Decius Vibellius seemed to act on the pretext that other cities, such as Locri, had expelled their garrisons and that he needed to act preemptively. Yet, they formed an alliance with the Mamertines of Messana and were viewed down upon as one and the same. Rome, being preoccupied largely with Pyrrhus, did not act for some years.
With Messana and its sister city of Rhegium across the strait, the Mamertines held a commanding position in Sicily and the shipping routes that passed through the Strait of Messina. With Messana as a base of operations the Mamertines were able to plunder, pirate, and raid the surrounding countryside with considerable success. Syracuse was unable to react immediately due to its internal political disorder from a new tyrant in Hicetas and a war with the neighboring city Acragas (though it could be argued that this was a rather common state for Syracuse). This left Sicily split between Carthage in the west and disunited Greeks and Mamertines elsewhere.
Carthage took advantage of this disarray (Carthage was also allied with Acragas) and attempted once again to siege Syracuse. It was at this point in 280 BC that the desperate Syracusans appealed to King Pyrrhus of Epirus who just happened to be right next door campaigning in southern Italy against the Romans in what became known as the Pyrrhic War. Pyrrhus obliged (as he was the son-in-law of Agathocles and more importantly a political opportunist) and over the next five years Pyrrhus pushed Carthage back to the westernmost tip of Sicily. However, Pyrrhus left for what he hoped for were better prospects in Greece which allowed an undefeated Carthage to recover its holdings in Sicily. In these years the Mamertines consolidated their hold over north-eastern Sicily and continued to expand their quasi-kingdom.
1. Polybius. The Histories. Translated by W. R. Paton. 1922.