Being shut up in Messana by Hiero, they asked aid of Rome on the ground that they were from Campania.

Although Rome was in alliance with Hiero, and had but recently executed 300 mercenaries for doing in Rhegium what the Mamertines had done in Sicily,--she determined to aid them, for Sicily was a rich and tempting prey.
Meanwhile, however, through the intervention of the Carthaginians, a truce had been formed between Hiero and the brigands, and the siege of Messana was raised.

The city itself was occupied by a fleet and garrison of Carthaginians under HANNO, The Romans, though the Mamertines no longer needed their aid, landed at Messana and dislodged the Carthaginians.
Thus opened the FIRST PUNIC WAR.

The Romans at once formed a double alliance with Syracuse and Messana, thus gaining control of the eastern coast of Sicily and getting their first foothold outside of Italy.
The most important inland city of Sicily was AGRIGENTUM.

Here the Carthaginians the next year (262) concentrated their forces under HANNIBAL, son of Cisco.