The Sicilian Greeks under the tyrants Gelo of Syracuse and Theron of Akragas had crushed the Punic expedition in the 1st battle of Himera in 480 BC.

Athens had sent fleets to Sicily in 427, 425, and 424 to intervene, which caused Hermocrates of Syracuse to request all Sicilian Greek cities to remain at peace at the congress of Gela in 424.

The Elymian city of Segesta had clashed with Selinus over territorial rights and marriage issues and had been worsted in the conflict.

This appeal came at a time when the mainland Greek cities were locked in the Peloponnesian War, and Syracuse, an ally of Sparta, was not focused on Sicily.

Hannibal Mago sent two expeditions to Sicily, the first one in 410 which drove the Selinute army from Segestan territory, and the second one obliterated Selinus after besieging the city in 409.

Carthage is said to have mobilized 120,000 men, including 4,000 cavalry, recruited from Africa, Sardinia, Spain, and even Sicilian Greeks for the Selinute campaign in 409, but a realistic estimate is around 40,000 soldiers.

The heavy infantry fought in close formation, armed with long spears and round shields, wearing helmets and linen cuirasses.

The Libyans, Carthaginian citizens, and the Libyo-Phoenicians provided disciplined, well-trained cavalry equipped with thrusting spears and round shields.

Large Sicilian cities like Syracuse and Akragas could field up to 10,000 – 20,000 citizens,[11] while smaller ones like Himera and Messana mustered between 3,000[12]–6,000[13] soldiers.

Hannibal then sent sappers, who dug tunnels under the walls and collapsed sections of it by setting fire to the wooden support beams.

[18] Carthaginian infantry then attacked through the gap, but the Himerans repulsed the Punic assault on the city, and then threw up makeshift walls to close the breaches.

[23] Diocles marched out of the city with half the men and all his troops at night, the Syracusan ships evacuated as many of the women and children as possible.

This held off the Greeks until the Carthaginian army stormed the city through the gap, and the reduced garrison of Himera was overcome by the weight of numbers.

He disbanded his army (the remaining Italian mercenaries chose to take service with Syracuse), garrisoned the Punic territory with sufficient troops and returned to Carthage with the fleet, where he was received with honors.

The survivors of Himera built a city called Thermae nearby, which housed a mixed population of Greeks and Phoenicians.