The Anglo-Saxon settlement of Britain was a consequence of the migration of Germanic peoples from continental Germania during the Early Middle Ages, after the demise of Roman rule in the 5th century. These peoples are traditionally divided into Angles, Saxons and Jutes, but research conducted in the early 20th century suggests that a wide range of Germanic peoples from the North Sea coasts of Frisia, Lower Saxony, and Jutland may have moved to Britain in this era.
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).
Map of Welsh castles. The castles of Wales were not only built by the English as part of their conquest and control of the local population, many were built by the Welsh Princes themselves. Internal feuding between them led to weakness and made conquest that much easier. How many other places in the old British Empire fell for the exact same reason ? rjp