The Balkan, or Mount Hæmus, as it was then called, formed the great northern frontier of Macedon and Thrace. From the summits of the range, looking northward, the eye surveyed a vast extent of land, constituting one of the most extensive and fertile valleys on the globe. It was the valley of the Danube. It was inhabited, in those days, by rude tribes whom the Greeks and Romans always designated as barbarians. They were, at any rate, wild and warlike, and, as they had not the art of writing, they have left us no records of their institutions or their history. We know nothing of them, or of the other half-civilized nations that occupied the central parts of Europe in those days, except what their inveterate and perpetual enemies have thought fit to tell us. According to their story, these countries were filled with nations and tribes of a wild and half-savage character, who could be kept in check only by the most vigorous exertion of military power.