Rome hesitates to intervene, the Mamertines are of Italian origin, which could encourage solidarity, but they are rebel soldiers installed by force. This delay is taken advantage of by the Carthaginian general Hannon the Great, son of Annibale Barca:he lands with an army in Sicily, reinforces the Carthaginian positions there and agrees with Hieron of Syracuse against Messina who has succeeded in getting rid of its Carthaginian garrison[4].
Rome finally sent in 264 BC. J.C. the consul Appius Claudius Caudex in Rhegium, from where he manages to disembark in Messina.
The military escalation reaches its fatal point:Hanno and Hiero besiege Messina, Appius Claudius enjoins them to lift the siege. Hieron refuses, replying that he is exercising just reprisals against the aggressions of the Mamertines[4]. War is declared.