Integration is a buzzword in the 21st century. However, academics still do not agree on its meaning and, above all, on its consequences. This book offers numerous examples showing that the inhabitants of the Roman Mediterranean were “integrated”, i.e. were aware of the existence of a common framework of coexistence, without this necessarily resulting in a process of cultural convergence. For instance, the Spanish poet Martial explicitly refused to be considered the brother of the Greek Charmenion (10.65): paradoxically, while reaffirming their differences, his satirical epigram confirms the existence of a common frame of reference that encompassed them both. Understanding integration in the Roman world requires paying attention to the complex and varied responses to diversity in Roman times.