Asiatic Background developed the wild mounted nomad. Here we have a second example of the great natural law that a people is and remains what its land of origin has made it. Just as the mounted nomad is the son and product of the arid salt-deserts, the Slav is the son and product of the marsh. The Slav and the mounted nomad, like the lands of their origin, are diametrical extremes, and the murderous irony of fate made them neighbours. The one was a soft anvil, the other a hammer hard as steel. A second not less weighty hammer (the Germans) came into play, and the anvil was beaten flat.
Dry and tolerably fertile forest land contains so much cultivable soil that it cannot easily be over-peopled: so here men form societies, and States arise. But primitive man cannot wrest a foot of land from the marsh; on the contrary, he extends it by making dams, transforming small streams into great fish-ponds. Thus, as the cultivable oases become smaller, the population huddles closer together. Dry forest land makes its inhabitants stronger, but the marsh has a degenerating influence. Forest land, however, is not inexhaustible; when what has been reaped from it is not made up for by dunging, or by allowing it to lie fallow — in short, when the soil is merely worked out — it can no longer support the growing population, and compels migration or expansion at the cost of the neighbourhood. But the unwarlike inhabitants of the marshland can conquer nothing, and can only spread gradually where they meet with no resistance. This is upon the whole the difference between the expansion of the Germans and that of the Slavs. The Germanic migration was eruptive as a volcano, the Slavonic a gradual percolation, like that of a flood rolling slowly forward. Some Germanic people or other leave their home: in the search for a new home they rouse their neighbours, and they in turn rouse theirs, and so it goes on until a hemisphere is thrown into commotion, strong States fall to pieces, mighty peoples perish, and even the Roman Empire quakes. And the Slavs? They have occupied and thickly populated immeasurable regions unnoticed by the annalists, and even now we ask in vain how this could have taken place so noiselessly, and whence have come the countless millions of Slavs.
The occupation by the Slavs of the district surrounding Polesie is prehistoric. They moved northward after the Baltic peoples had abandoned their original home in the hornbeam zone and retired towards the Baltic Sea; eastward over the Oka and to the sources of the Oskol; southward to Kiev — further southwards they could not maintain themselves permanently, as fifteen centuries ago the grass steppe reached as far as Kiev and consequently served the mounted nomads as a camping ground up to that point. Towards the south-west the Slavs reached the Carpathians, and in the west they spread across the Vistula. In the time of the Romans the Vistula was regarded as the eastern frontier of the Germans.
