It was Carthage’s determination to hold on to the western Sicilian ports that made it resist any potential external threats with such dogged determination and disregard for the heavy cost in manpower and other resources that it entailed. In the 340s the threat was from the Greek city of Corinth, which was becoming increasingly involved in the internal affairs of its daughter city Syracuse.131 The Carthaginians attempted to warn off Timoleon, the Corinthian representative sent to Sicily, but without success.132 Subsequent efforts militarily to intimidate him also failed, with Timoleon successfully establishing a new democratic government in Syracuse as well as creating a broad anti-Carthaginian alliance among a number of the Sicilian Greek city states.133
Further disaster struck when in 340 a large Carthaginian army–unusually, made up of a large contingent of citizen troops–was successfully ambushed by Timoleon.134 Marching deep into enemy territory, the Syracusans waited for the Carthaginians at the river Crimisus. According to Diodorus, on that summer morning the river valley was covered in a thick mist. The only sign that the Carthaginian army was on the move was a deep rumble which rose up to the Syracusans through the swirling mist. Later in the morning, as the gloom lifted, the Crimisus below came into view–and with it the aweinspiring sight of the Carthaginian regiments crossing the river.
First came four-horse chariots fitted out for battle, and then the elite citizen regiment, the Sacred Band, distinguishable by their white shields, heavy bronze and iron armour, and the ordered discipline of their march. Anxious to catch these crack battalions before they had a chance to clear the river, Timoleon sent his cavalry in among them. During the battle a terrible hailstorm came to the aid of the Greeks, who had their backs to it. The Carthaginian line was broken, and many were trampled underfoot and drowned in the river. The Sacred Band, perhaps mindful of their citizen status, or knowing that their heavy armour ruled out any chance of flight, valiantly stood their ground until they were cut down to a man. Crimisus, in terms of citizen lives lost, stood as the worst military disaster that the Carthaginians suffered in Sicily. Over 10,000 Carthaginian soldiers were reported to have been killed, with a further 15,000 captured. The loss of the Sacred Band, the flower of Carthage’s citizen elite, ensured that citizen regiments would now be mobilized only in the gravest crises.135
The Carthaginians, however, did manage to recover from this terrible setback by continuing the war against the Syracusans by proxy. Fresh mercenaries were sent to Sicily to help various autocrats, the natural enemies of democratic Syracuse. This tied up the Syracusan forces so that the Carthaginians could quietly reconsolidate their hold on the western half of the island, and the tactics were vindicated when in 338 BC a new treaty was signed with Syracuse. Much of western Sicily was recognized as a zone of Carthaginian influence, and in return the Carthaginians jettisoned their new allies.136