Carthage's success led to the creation of a powerful navy to discourage both pirates and rival nations. This, coupled with its success and growing hegemony, brought Carthage into increasing conflict with the Greeks, the other major power contending for control of the central Mediterranean.

The island of Sicily, lying at Carthage's doorstep, became the arena on which this conflict played out. From their earliest days, both the Greeks and Phoenicians had been attracted to the large island, establishing a large number of colonies and trading posts along its coasts. Small battles had been fought between these settlements for centuries.

By 480 BC Gelo, the tyrant of Greek Syracuse, backed in part by Greek support, was attempting to unite the island under his rule. This imminent threat could not be ignored, and Carthage - possibly as part of an alliance with Persia, then engaged in a war with Greece - fielded its largest military force to date, under the leadership of the general Hamilcar. Traditional accounts give Hamilcar's army a strength of three hundred thousand men; though these are almost certainly exaggerated, it must nonetheless have been of formidable force.

En route to Sicily, however, Hamilcar suffered losses (possibly severe) due to poor weather. Landing at Panormus (modern-day Palermo), he was then decisively defeated by Gelo at the Battle of Himera. He was either killed during the battle or committed suicide in shame. The loss severely weakened Carthage, and the old government of entrenched nobility was ousted, replaced by the Carthaginian Republic.

Source: Wikipedia