However, no historical event occurs in isolation. What were the reasons that propelled Rome into a risky war outside the Italian mainland?
In the process of gaining control of Italy, each time the Romans solved a frontier problem a new one was created The war which they fought against Pyrrhus and the southern Greek states revealed the same problem.
Many of the southern Italian Greek cities, being colonies originally from the Greek world, formed in Italy what even the Romans themselves sometimes called Magna Graecia ('Great Greece'). These cities relied heavily on trading for their economy, and so were in contact with the Greek colonies settled on the island of Sicily and elsewhere in the western Mediterranean.
But the Carthaginians too were dependent on trade and interested in developing a commercial empire in Sicily and elsewhere. Their expansionist activities alarmed the Greeks in Sicily, who at one point called in Pyrrhus to assist them against the Carthaginians, just as he was called in to help the Tarentines against the Romans.
As a result of the defeat of Pyrrhus, the Romans gained control of the rather unstable Greek communities in the very south of Italy, and this in turn brought them indirectly into the sphere of activities of the Greeks who lived in Sicily, not far away across the narrow Straits of Messana. So it was against the background of warfare with Pyrrhus and of Greek and Carthaginian commercial activity in south Italy and Sicily that Rome and Carthage were brought into confrontation with each other.
The First Punic War was started in 264 BC by the crisis in the city of Messana (Messina), a strategically important location on the straits separating Sicily from Italy.
Since 288 Messana had been in the hands of the Mamertini (Mamertines) who used the town as a base for raiding nearby towns. The Romans had expelled a similar group of mercenaries from Rhegium (across the Straits of Messina) a few years earlier. Hieron (Hiero) II 'Tyrant'of Syracuse, wanted to get rid of the Mamertines just as the Romans had rid the Italian city of Rhegium of mutineering soldiers. Hiero besieges the city: the Mamertines applied for help to both Rome and Carthage.
The issue was whether the Romans were willing to undertake these new and indefinite obligations and to do so in support of a clearly disreputable gang of bandits; to do the opposite of what they had just done in Rhegium.
Why should the Romans involve themselves in Sicily? There were a number of conflicting considerations:
- Rome had no fleet, presenting obvious logistical problems
- The poor character of the Mamertines (although the Romans were not above reproach themselves)
- Rome had obligations to their new subject allies, the Greek cities of southern Italy whose prosperity depended on trade with Sicily; The Carthaginian policy of mare clausum would eventually hurt Greeks in Italy
- Messana was important for controlling the straits between Sicily and Italy; there was a perceived danger to Italy if a strong power like Carthage dominated these straits
- The Senate was worried about Carthage's growing power in the Mediterranean
- There were dangers in entering into a larger war in an unfamiliar island; Pyrrhus had found Sicily to be a risky involvement
- The Romans were tired of war
When the Mamertine appeal for help came to the senate, it was unable to make a decision. Some argued that since Rome had recently punished a Campanian garrison for acting similarly, the could hardly blame the Carthaginians. Others said that if the Carthaginians gained control of Sicily, the next step would be an attack on Italy.
If the Romans helped the Mamertines, who were - at best - pirates, they would offend Hiero, their friend as well as their own Greek allies whose seaborne trade was suffering under Mamertine piracy. They would probably also offend Carthage, and Carthage could put much trouble in their way. The Mamertines, while they were of Italian origin, were being threatened by the city which had shown most capacity for managing Greek interests on a large scale. If Rome refused help, would Carthage herself step in ? And what were the prospects of legitimate Italian trade, with Carthage in control of the strait ?
After the deadlock, the senate allowed the People to decide the matter. Under the prompting of the consul, they agreed to accept and send an army to Sicily. (On only one occasion did the centuriate assembly refuse a proposed declaration of war [in 200 against Philip V of Macedon] and even then the assembly was badgered into acquiescing.)
Roman policy emerges: to prevent the development of a strong state on the fringe of her self-defined sphere of influence, always ally with the weaker power against a stronger one and do so without due consideration of the morality of the competing claims.
Roman motives have aroused much modern debate. An important school holds that Rome's wars were basically defensive and usually resulted from external considerations rather than Roman "imperialism." Such a position is hard to maintain for this war. To call it a defensive war when the Romans attacked to prevent the possibility of a Carthaginian attack is to twist words. There was no particular reason to think that Carthage had either the intention to attack Italy or (perhaps more importantly) the means to do so.
It is noteworthy that when PolybiusLatium and the Samnites and there is every reason to believe the same of the First Punic War. Certainly, the Roman move into Messana is reminiscent of the Roman move to establish colonies at Cales and Fregellae as preliminary (and aggressive) steps toward conflict with the Samnites.