The history of republican Italy is one of conquest and Roman expansion but also one of many different peoples and communities and the strategies they used both to integrate with and to resist the influence of Rome. What it is emphatically not is a linear process of Roman expansion and the disappearance of local cultures and identities. Ancient Italy was not an ethnic or political unit but a region of extreme diversity. It contained many different ethnic groups, each with its own language, culture, economy, and forms of social and political organisation (Fig. 8), and as Roman power began to expand, complex systems for controlling conquered areas and mediating relations with other states evolved piecemeal. As a result, Roman Italy, even after it became a politically unified entity in 90 B.C., had a high level of cultural diversity and strong regional identities that coexisted with central control and Roman influence.

One of the most central — but also one of the most problematic — concepts with which the historian of Roman Italy has to grapple is that of Romanisation. The process of cultural, as opposed to political, integration with Rome is notoriously difficult to define in theory and to identify in action. Roman culture itself was neither unified nor static but rather disparate and constantly changing. It also operated in different ways at different levels of society. Roman cultural influence may have meant something very different to different social groups.