The work starts from Polybius’ point about 202 B.C. being the moment when world-conquest became practical for Rome, and then analyze how the conflict with Carthage (i.e. 264 B.C. onwards) was fundamental in transforming the Roman State in various ways to reach this point. A particular emphasis is given to the institutional element, in order to take into account and unite in one place all those developments that took place both prior to and during the Hannibalic War (prorogation, institutional expansion, step-changes in military deployment, increasing flexibility, etc.) that clearly affected Rome’s expansionist policy. The goal of the work is to show that what really changed in 201 B.C. was not the “ambition to rule” in a general sense – as that was always present in Roman society – but the capability by the Romans to fulfil their ambitions, and that this awareness was reached thanks to the new military and political institutions developed especially during the Hannibalic war.