In the 500 years after the political collapse of the Western Roman Empire in the fifth century CE, various new groups entered Italy, recasting the ranks of the wealthiest and most powerful individuals and local elites. In the social hierarchy of the late fifth century, Ostrogothic elite would exist in parallel with the late Roman aristocracy, while later arrivals—Lombards, Byzantines, and Franks, among others—would form entirely new aristocracies, bound primarily by local landownership and management, leaving behind the administrative apparatus of the late Roman Empire. Consequently, Italian aristocracies, especially at their highest levels, tended to reflect the conditions of their political systems through the tenth century, when changing pressures caused many family groups of the social and political elite to take on the qualities of hereditary nobility. This article traces the various developments of aristocracies, their composition, and contemporary definitions of dominant groups.