[4] In 288 BC, the Mamertines, Italian mercenaries that were hired to attack the Carthaginians, went to the city of Messana to protect it but instead massacred its men, took the land, and forced the women to become their wives.

Hiero II did not want openly to attack the Carthaginians and invite a war, so he retreated back to Syracuse.

[6] Carthage had already been trying to control Sicily for centuries, and their main opposition had been the Greek colonies spread around the island.

Additionally, Messana was an excellent staging area if the Carthaginians wanted to invade Italy and attack Rome.

[7] While the Romans had been steadily expanding their territory for over a century, their army had never fought a battle outside of the Italian Peninsula.

In 264 BC, the Roman Senate voted to send an expedition to Sicily under the command of Appius Claudius Caudex, one of the consuls for that year.

Adrian Goldsworthy has maintained that it was highly unlikely, and that, although the Romans knew war with Syracuse was almost a certainty, they believed their military would deter or swiftly defeat any opposition in Sicily.

In 263 BC, the Syracusans, who had initially opposed the Roman takeover of Messana, made peace with them and began supplying their troops.

The Roman consuls, Lucius Postumius Megellus and Quintus Mamilius Vitulus focused their forces on Agrigentum.

[11] The Roman consuls realised that they had to cut off Agrigentum from the outside world and blockade the city to cause starvation in order to force its inhabitants to surrender.

The Romans began digging a system of ditches and small forts surrounding the city to prevent the inhabitants from preparing for the siege.

[14] Carthage sent a relief force from Africa commanded by Hanno, whom historians believe to have been the son of Hannibal.

Hannibal, communicating with the outside by smoke signals, sent urgent pleas for relief, and Hanno was forced to accept a pitched battle.

[17][1] Byzantine writer Zonaras wrote that Hanno deployed his army to battle but the Romans declined to fight because of the previous defeat of their cavalry.

[17] A more likely version of the battle is that Hanno deployed the Carthaginian infantry in two lines, with the elephants and reinforcements in the second and the cavalry probably placed in the wings.

Most of the enemy army fled and Hannibal Gisco, together with the garrison of Agrigentum, also managed to break the Roman line and escape for security.

The night after the battle, Hannibal managed to escape Agrigentum with his mercenaries by filling the Roman trenches with straw.

The next morning, the Romans pursued Hannibal and his garrison, and attacked the rear-guard, but eventually turned back to take control of Agrigentum.

Because Hannibal and his garrison managed to escape relatively unharmed, there was no Roman triumph for the two consuls, and it detracted from the success of the battle.

This victory in the first large-scale campaign fought outside Italy gave the Romans extra confidence to pursue overseas interests.