Why did the Messana crisis become a war?

What started the First Punic War?

Acquisition, financial gain and fear of a major power close to Rome's doorstep combined at Messana.

Acquisition, financial gain and fear combined in the struggle over Messana. Carthage valued a position from which it could influence Rome. That same proximity made the position alarming to the Romans. Geography made one power's advantage feel like a threat to the other.