The Roman Empire reached its greatest size under the reign of Trajan in 117 AD. To aid in administration, it was divided into provinces. The number of provinces changed over time as territories were gained or lost, and as larger provinces were divided into smaller ones. There were 46 provinces under Trajan, a figure that would grow to 96 by the reign of Diocletian (285-305).
Roman roads, together with Roman aqueducts and the vast standing Roman army, constituted the three most impressive features of the Roman Empire. In Britain, as in their other provinces, the Romans constructed a comprehensive network of paved trunk roads (i.e. surfaced highways) during their nearly four centuries of occupation (43 - 410 AD).
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.