For generations, Roman historians tended to concentrate their energies on constitutional and political history, and to focus their interest on the Mediterranean heartland of the empire. This situation has changed dramatically in recent times. The increased sophistication of archaeological techniques and the rapid accumulation of archaeological data are providing scholars with a far clearer picture of the economic, social, and technological aspects of Roman life. Such archaeological research is most advanced in northwestern Europe and, although to a lesser degree, in southeastern Europe. As a consequence, an increasing amount is being learned about Roman life in Britain, the Netherlands, Germany, and the other countries and regions that once formed the western frontiers of the empire. Much of that information is not being applied effectively, however. Many historians are unwilling to admit the validity of any data not supported by a textual source, and many archaeologists regard literary evidence as unreliable when compared with the tangible "facts" they have uncovered. Such differences have impeded attempts to provide those interested in the subject with an integrated and comprehensible account of the Roman frontier.
Given the fact that both authors of the present work have long shared an interest in Roman history as well as American westward expansion, it was perhaps inevitable that our attention should be drawn to the study of the Roman frontier and that we should approach the subject with some of the perspectives provided by the American frontier. American students are close to their own frontier experience and