You will understand, of course, what I mean when I talk of "the whole world" at this point of the story, and what that Greek historian, Polybius, of whom I told you in the last chapter, meant by it. He knew, no doubt, that there was a great deal of the world, in the sense of land inhabited by human beings, beyond the wide lands over which the Roman power really did extend. But neither he nor any one else in the Greek or Roman world of that day thought that these lands and their inhabitants counted for anything. They did not matter. These peoples were called barbarians. They were considered rather as we consider the North American Indians or the negroes. They were far more formidable to the Romans than either of these are to us, because the people away to the east and north-east of Syria, to the north of Asia Minor and Thrace and of Italy itself, all these had limitless lands behind them, on the sides farthest {192} from the central power of Rome, to retreat into when she came with any power against them. For the most part they were peoples who led a wandering life. It was no trouble to them to strike their tents and go back into the wilds. But it was terrible trouble for the legions to follow them very far into those wilds; and the legions could not easily force them to a decided battle if they did follow them. Therefore the Romans doubtless knew that however far they might push out their power in the east and north there would always be peoples on the edge of the lands which they could really make their own who would be apt to give trouble and would require small campaigns to be waged against them from time to time. Probably they made up their minds to that. But inside that wide barbarian fringe, and with the Atlantic Ocean on the west and the nearly uninhabited deserts of Africa on the south--within the wide expanse of which these form the boundary, the Roman power was such that if Rome said a thing had to be done, there was no man who questioned it. Done that thing had to be. That is what is meant by a phrase that you have most likely heard, the "Pax Romana," the Roman peace. It meant the peace which Rome could, and did, enforce within these regions under her power--a peace that could not be broken because every man knew that whatever she said was to be done, must be done. There was no help for it. Of course the peace was not perfect, it was not untroubled. No peace ever is. But it was peace of a kind that the world had never known before. The whole world--the whole world that mattered--was for the first time under one single authority. It was also for the last time; for it is a condition that the {193} world has never been in again since the break-up of the Roman power. So I think I was justified in asking you to stop a moment in the course of the story in order to consider the position of affairs to which it has brought us. It is interesting, is it not? * * * * * [Sidenote: Mithridates]