The members of these communities (principally the Dutch, Frisian, Rhenish and other Germanic peoples, but also on the other frontiers, the nomads of the desert, and in the West, islanders and mountaineers, Irish and Caledonian) were all tinged with the great Empire on which they bordered. Its trade permeated them. We find its coins everywhere. Its names for most things became part of their speech. They thought in terms of it. They had a sort of grievance when they were not admitted to it. They perpetually begged for admittance. They wanted to deal with the Empire, to enjoy its luxury, now and then to raid little portions of its frontier wealth. They never dreamt of “conquest.” On the other hand the Roman administrator was concerned with getting barbarians to settle in an orderly manner on the frontier fields, so that he could exploit their labor, with coaxing them to serve as mercenaries in the Roman armies, or (when there was any local conflict) with defeating them in local battles, taking them prisoners and making them slaves. I have said that the mere number of these exterior men (German, Caledonian, Irish, Slav, Moorish, Arab, etc.) was small compared with the numbers of civilization, and, I repeat, in the eyes of the citizens of the Empire, their lack of culture made them more insignificant still. At only one place did the Roman Empire have a common frontier with another civilization, properly so called. It was a very short frontier, not one-twentieth of the total boundaries of the Empire. It was the Eastern or Persian frontier, guarded by spaces largely desert. And though a true civilization lay beyond, that civilization was never of great extent nor really powerful. This frontier was variously drawn at various times, but corresponded roughly to the Plains of Mesopotamia. The Mediterranean peoples of the Levant, from Antioch to Judea, were always within that frontier. They were Roman. The mountain peoples of Persia were always beyond it. Nowhere else was there any real rivalry or contact with the foreigner, and even this rivalry and contact (though “The Persian War” is the only serious _foreign_ or equal war in the eyes of all the rulers from Julius Cæsar to the sixth century) counted for little in the general life of Rome.