Three blocs of power had been delicately balanced in Sicily by 483 BCE—Ionians dominating the north, Carthage the west, Dorians the east and south.

The Sicels and Sicans, sandwiched in the middle, remain passive, but the Elmyians join the Carthaginian alliance.Carthage responds to the call for aid by Terrilus, tyrant of Himera, after Theron had deposed him in 483 BCE to set up an expedition to Sicily.

Carthage cannot ignore this imminent threat because the Gelo-Theron alliance is about to take over the whole of Sicily, and Hamilcar is a guest friend of Terrilus.Carthage may have also chosen this time to attack because a Persian fleet attacks mainland Greece in the same year.

The theory that there was an alliance with Persia is disputed, because Carthage neither likes foreign involvement in their wars, nor wants to contribute to foreign wars, unless they have strong reasons to do so, but because control of Sicily is a valuable prize for Carthage and because Carthage fields its largest military force to date, under the leadership of the general Hamilcar, Carthage is eager for war.

Traditional accounts give Hamilcar's army a strength of three hundred thousand men, which seems high.

If Carthage had allied with Persia, they might have supplied Carthage mercenaries and aid, which the Persians undoubtedly had, but there is no evidence to support this cooperation between the Carthaginians and the Persians.En route to Sicily, however, the Punic fleet suffers losses, possibly severe, due to poor weather.

After landing at Ziz, the Punic name for Panormus, modern-day Palermo, Hamilcar is then decisively defeated by Gelo at the Battle of Himera, which is said to have occurred on the same day as the Battle of Salamis.

Hamilcar is either killed during the battle or commits suicide in shame.

The loss causes changes in the political and economic landscape of Carthage, the old government of entrenched nobility is ousted, replaced by the Carthaginian Republic.

The king still remains, but he has very little power and most power is entrusted to the Council of Elders.

Carthage paid two thousand talents as reparations to the Greeks, and does not again intervene in Sicily for seventy years.In Sicily, Carthage has lost no territory and the Greeks have gained none.

Syracuse had not attacked Rhegion or Selinus, allies of Carthage.

The booty from the war helps to fund a public building program in Sicily, Greek culture flourishing as a result.

Trading activity sees the prosperity of the Greek cities increase and the wealth of Akragas begins to rival that of Sybaris.

Gelo will die n 478 BCE and, within the next twenty years, the Greek tyrants are overthrown and the Syracuse-Akragas alliance fragments into eleven feuding commonwealths under oligarchs and democracies.

Their bickering and future expansionist policies leads to the Second Sicilian war