The products of a highly civilised community must always tend to drift across its political frontiers to less advanced peoples beyond. In the early centuries of our era the output of Roman workshops, following perhaps the older amber routes, was finding its way north of the Rhine and reaching Scandinavia. The same process was going on in Caledonia. The troops marching northward carried their supplies with them, and on the sites of their forts the excavator unearths their pottery and glass, their vessels of bronze, their ornaments, tools and weapons,—the familiar things of provincial Roman civilization. But out beyond the limits of the forts and camps the same products from time to time come to light—picked up near the lines of communication, gathered from the sites of native dwellings, or found far out among the hills or by coasts where the Roman soldier never penetrated, telling their tale of traffic or of plunder.