Himilco came to prominence after being selected as deputy to his cousin Hannibal Mago in 406 BC for the Carthaginian expedition to Sicily.
He took command of the expedition after Hannibal's death and sacked Akragas, Gela and Camarina while fighting off determined Greek opposition led by successive leaders of Syracuse.
The peace treaty Himilco concluded with Dionysius of Syracuse in 405 BC expanded Carthaginian holdings in Sicily to their maximum extent.
Although initially successful, Himilco suffered a reverse at Syracuse in 396 BC when his forces were decimated by the plague and then defeated by Dionysius.
Himilco publicly assumed full responsibility for the debacle, and after visiting all the temples of the city dressed as a slave to offer penance, he is said to have starved himself to death.
Hannibal Mago, son of Gisco, was the suffet of Carthage in 409 BC and led the expedition to Sicily which destroyed both Selinus and Himera and made Segesta a vassal entity.
It is not known if Himilco had played a part in these activities, although the army had attracted a large number of Carthaginian citizens at that time.
Hannibal initially refused, pleading old age, but accepted when the Carthaginian Senate elected Himilco as his deputy.
[14] Himilco kept a part of his army in the main camp to watch Akragas while the mercenaries marched east to fight the Greeks.
Himilco temporarily placated the unruly mercenaries by bribing them with the gold and silver tableware of the Carthaginian officers.
The Greeks now faced a problem – there was not enough food stocked at Akragas to feed both the population and the army until further supplies could be gathered – and organizing that would take time because of the winter season.
[16] Mistrust between Greeks from various quarters now burst open when this news became public – thus reducing their ability to take a joint decision regarding continuing the conflict.
The main conditions were:[26] In return for recognizing Dionysius as the ruler of Syracuse, Himilco ensured the total reversal of all the conquests of Gelo and Hieron.
When Dionysius broke the peace treaty in 404 BC by attacking the Sicel city of Herbessus, Carthage, possibly weakened by the plague, did not respond.
In 403 BC Carthage provided mercenaries to restore Dionysius to power after he was besieged in Syracuse by a coalition of Sicilian Greek cities led by Syracusan rebels.
The Greeks and Sicilians rebelled and joined Dionysius, leaving only 5 cities (Panormus, Solus, Segesta, Entella and Ankyara) in Sicily loyal to Carthage.
[27] The Greeks besieged simultaneously Motya, Segesta and Entella in Sicily[28][29] while Himilco began to mobilize Carthaginian forces.
While Carthage raised mercenaries and organized logistics, Himilco sent 10 triremes to attack Syracuse itself, hoping to draw off the Greeks from Motya.
[31] The Greeks had beached their transports to the south of Motya and their warships to the north, while the crews were busy building siege works.
While Himilco's crews suffered casualties, Dionysius had his men drag 80 triremes across the base of the isthmus to the north of Motya into the open sea beyond.
The Carthaginians sailed back to Carthage, and Motya eventually fell after days of fierce street fighting.
Himilco marshalled an army of 50,000 infantry, 4,000 cavalry and 400 chariots, while the Carthaginian navy mobilized 400 triremes and 600 transports.
To keep any information from leaking to the Greeks, Himilco wrote down the armada's destinations in sealed letters, which were issued to his captains at the last moment.
[35] The Carthaginian armada split into two groups: the transports headed straight for Panormus while the warships sailed north before turning east.
Himilco chose not to march to Syracuse along the southern coast of Sicily, as Dionysius had destroyed all the crops and hostile Greek cities stood on his path.
After garrisoning Carthaginian territory, he made treaties with the cities of Thermae and Cephaleodium on the north coast of Sicily to secure his supply route.
[40] Had Himilco also defeated the Messinian army his would have won a complete victory, but he allowed the surviving Greeks to take refuge in nearby mountain fortresses, which Carthaginians could not quickly reduce.
However, Mago managed to defeat[43] the Greek fleet under Leptines, and Dionysius withdrew to Syracuse before Himilco arrived with the Carthaginian army.
In the spring of 396 BC, the Carthaginians captured the areas of the city not protected by walls and destroyed the temple of Demeter.
A bribe of 300 silver talents ensured the safe passage of 40 ships bearing all the Carthaginian citizens to Carthage.