who reunited western europe for the first time since the roman empire
Western Roman Empire In historiography, the Western Roman Empire consists of the western provinces of the Roman Empire at any one time during which they were administered by a separate independent Imperial court, coequal with (or only nominally subordinate to) that administering the eastern half. Both "Western Roman Empire" and "Eastern Roman Empire" (or "Byzantine Empire") are modern terms describing de facto independent entities; however, at no point did the Romans consider the Empire split into two, but rather considered it a single state governed by two separate Imperial courts out of administrative expediency, a system of government known as a diarchy.