It was not uncommon during the rigors of winter for their sentinels standing on night guard at cave entrances to freeze to death. They had courage, but above all they were artists; the Adamic mixture suddenly accelerated creative imagination. The height of the blue man's art was about fifteen thousand years ago, before the days when the darker-skinned races came north from Africa through Spain.

About fifteen thousand years ago the Alpine forests were spreading extensively. The European hunters were being driven to the river valleys and to the seashores by the same climatic coercion that had turned the world's happy hunting grounds into dry and barren deserts. As the rain winds shifted to the north, the great open grazing lands of Europe became covered by forests. These great and relatively sudden climatic modifications drove the races of Europe to change from open-space hunters to herders, and in some measure to fishers and tillers of the soil.

These changes, while resulting in cultural advances, produced certain biologic retrogressions. During the previous hunting era the superior tribes had intermarried with the higher types of war captives and had unvaryingly destroyed those whom they deemed inferior. But as they commenced to establish settlements and engage in agriculture and commerce, they began to save many of the mediocre captives as slaves. And it was the progeny of these slaves that subsequently so greatly deteriorated the whole Cro-Magnon type. This retrogression of culture continued until it received a fresh impetus from the east when the final and en masse invasion of the Mesopotamians swept over Europe, quickly absorbing the Cro-Magnon type and culture and initiating the civilization of the white races.

While the Andites poured into Europe in a steady stream, there were seven major invasions, the last arrivals coming on horseback in three great waves. Some entered Europe by way of the islands of the Aegean and up the Danube valley, but the majority of the earlier and purer strains migrated to northwestern Europe by the northern route across the grazing lands of the Volga and the Don.

Between the third and fourth invasions a horde of Andonites entered Europe from the north, having come from Siberia by way of the Russian rivers and the Baltic. They were immediately assimilated by the northern Andite tribes.

The earlier expansions of the purer violet race were far more pacific than were those of their later semimilitary and conquest-loving Andite descendants. The Adamites were pacific; the Nodites were belligerent. The union of these stocks, as later mingled with the Sangik races, produced the able, aggressive Andites who made actual military conquests.

But the horse was the evolutionary factor which determined the dominance of the Andites in the Occident. The horse gave the dispersing Andites the hitherto nonexistent advantage of mobility, enabling the last groups of Andite cavalrymen to progress quickly around the Caspian Sea to overrun all of Europe. All previous waves of Andites had moved so slowly that they tended to disintegrate at any great distance from Mesopotamia. But these later waves moved so rapidly that they reached Europe as coherent groups, still retaining some measure of higher culture.