The real history of Britain begins with the Roman occupation, for the Romans were the first to leave substantial documentary and archaeological evidence. After the governorship of Agricola the written sources almost entirely disappear until the early Anglo-Saxon era of the fifth century; but archaeologists have been able to gather a great deal of information about the intervening centuries from excavations of old walled towns, roads, and fortresses dating from the Roman period. Mr. Blair skillfully describes the transition from Roman to Saxon England and shows why Rome's greatest legacy to...