”There were 46 provinces under Trajan, a figure that would grow to 96 by the reign of Diocletian (285-305). In Trajan's time, provinces in the interior of the country were run by governors chosen by the Senate, a legislative body run by leading aristocrats. In contrast, border provinces were run by governors named directly by the emperor.”
The barbarian tribes who carved up the old empire — the Franks, Visigoths, Ostrogoths, the Vandals, and so forth — were much more Romanized than the tribes that had menaced Rome centuries earlier. The rulers of these new kingdoms generally sought to co-opt Roman elites that still held significant wealth and power across the former Western Empire.