The Carthaginian presence in Sicily was of long standing. Carthage had been fighting on behalf of other Phoenician colonies, which were continually under pressure from the Greek colonies in the east to withdraw westward, since 480. The Carthaginians suffered a major setback in 480, when Hamilcar's invasion of Sicily was repulsed by Gelon, the tyrant of Syracuse, at Himera. This attack was alleged by Diodorus to have been timed to coincide with the subjugation of Greece by Xerxes through a secret pact between the Persians and Carthaginians, and the allegation is at least plausible, considering that the Phoenicians themselves led Xerxes' naval force. But even then the Carthaginians controlled (in addition to a large swath of coastline on either side of their own city) not only Southern Spain, but also Corsica and Sardinia. And they won much of western Sicily back in a series of campaigns which took advantage of the weakened state of Syracuse in the aftermath of the Athenian blockade (410-405 BC).

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When it's too late