It is easy to see the interdependence created by this specialization in production, and the economic necessity it has imposed for an undivided empire. The forest zone could not exist without the corn of the Black Lands and the Prairies, nor without the cattle of the Steppes. Nor could those treeless regions exist without the wood of the forests. So it is obvious that when Nature girdled this eastern half of Europe, she marked it for one vast empire; and when she covered those monotonous plateaus with a black mantle of extraordinary fertility, she decreed that the Russians should be an agricultural people. And when she created natural conditions unmitigated and unparalleled in severity, she ordained that this race of toilers should be patient and submissive under austerities; that their pulse should be set to a slow, even rhythm, in harmony with the low key in which Nature spoke to them. It is impossible to say when an Asiatic stream began to pour into Europe over the arid steppes north of the Caspian. But we know that as early as the fifth century B. C. the Greeks had established trading stations on the northern shores of the Black Sea, and that these in the fourth century had become flourishing colonies through their trade with the motley races of barbarians that swarmed about that region, who by the Greeks were indiscriminately designated by the common name of Scythians. The Greek colonists, who always carried with them their religion, their Homer, their love of beauty, and the arts of their mother cities, established themselves on and about the promontory of the Crimea, and built their city of Chersonesos where now is Sebastopol. They first entered into wars and then alliances with these Scythians, who served them as middle-men in trade with the tribes beyond, and in time a Graeco-Scythian state of the Bosphorus came into existence. Herodotus in the fifth century wrote much about these so-called Scythians, whom he divides into the agricultural Scythians, presumably of the Black Lands, and the nomad Scythians, of the Barren Steppes. His extravagant and fanciful pictures of those barbarians have long been studied by the curious; but light from an unexpected source has been thrown upon the subject, and Greek genius has rescued for us the type of humanity first known in Russia.