During the last glacial advance (known as the Würm) which, like the preceding glaciations, is believed to have been a period of land depression, the White Sea extended far to the south of its present limits, while the enlarged Caspian Sea, then and long afterward connected with the Sea of Aral, extended northward to the great bend of the Volga. The intermediate area was studded with large lakes and morasses. Thus an almost complete water barrier of shallow sea located just west of the low Ural Mountains, separated Europe from Asia during the Würm glaciation and the following period of glacial retreat. The broken connection was restored just before the dawn of history by a slight elevation of the land and the shrinking of the Caspian-Aral Sea through the increasing desiccation which has left its present surface below sea level.
An important element in the maintenance of the isolation of this Nordic cradle on the south is the fact that from earliest times down to this day the pressure of population has been unchangeably from the bleak and sterile north, southward and eastward, into the sunny but enervating lands of France, Italy, Greece, Persia and India.
In these forests and steppes of the north, the Nordic race gradually evolved in isolation and at an early date spread north over the Scandinavian Peninsula together with much of the land now submerged under the Baltic and North Seas.
Nordic strains form everywhere a substratum of population throughout Russia and underlie the round skulled Slavs who first appear a little over a thousand years ago as coming not from the direction of Asia but from south Poland. Burial mounds called kurgans are widely scattered throughout Russia from the Carpathians to the Urals and contain numerous remains of a dolichocephalic race,—in fact, more than three-fourths of the skulls are of this type. Round skulls first become numerous in ancient Russian graveyards about 900 A. D. and soon increase to such an extent that in the Slavic period from the ninth to the thirteenth centuries one-half of the skulls were brachycephalic, while in modern cemeteries the proportion of round skulls is still greater. The ancient Nordic element, however, still forms a very considerable portion of the population of northern Russia and contributes the blondness and the red-headedness so characteristic of the Russian of to-day. As we leave the Baltic coasts the Nordic characters fade out both toward the south and east. The blond element in the nobility of Russia is of later Scandinavian and Teutonic origin.
When the seas which separated Russia from Asia dried, when the isolation and exacting climate of the north had done their work and produced the vigorous Nordic type, and when in the fulness of time bronze for their weapons reached them these men burst upon the southern races, conquering east, south and west. They brought with them from the north the hardihood and vigor acquired under the rigorous selection of a long winter season and vanquished in battle the inhabitants of older and feebler civilizations, but only to succumb in their turn to the softening influences of a life of ease and plenty in their new homes.
The earliest recorded appearance of Aryan-speaking Nordics is our first dim vision of the Sacæ introducing Sanskrit into India, the Cimmerians pouring through the passes of the Caucasus from the grasslands of South Russia to invade the Empire of the Medes and the Achæans and Phrygians conquering Greece and the Ægean coast of Asia Minor. About 1100 B. C. Nordics enter Italy as Umbrians and Oscans and soon after other Nordics cross the Rhine into Gaul. The latter were the western vanguard of the Celtic-speaking tribes which had long occupied those districts in Germany which lay south and west of the Teutonic Nordics. These Teutons at this early date were confined probably to Scandinavia and the immediate shores of the Baltic and were just beginning to press southward.
This first Celtic wave of Nordics seems to have swept westward along the sandy plains of northern Europe, and entered France through the Low Countries. From this point as Goidels they spread north into Britain, reaching there about 800 B. C. As Gauls they conquered all France and pushed on southward and westward into Spain and over the Maritime Alps into northern Italy, where they encountered the kindred Nordic Umbrians, who at an earlier date had crossed the Alps from the northeast. Other Celtic-speaking Nordics apparently migrated up the Rhine and down the Danube and by the time the Romans came on the scene the Alpines of central Europe had been thoroughly Celticized. These tribes pushed eastward into southern Russia and reached the Crimea as early as the fourth century B. C. Mixed with the natives, they were called by the Greeks the Celto-Scyths. This swarming out of what is now called Germany of the first Nordics was during the closing phases of the Bronze Period and was contemporary with and probably caused by the first great expansion of the Teutons from Scandinavia by way both of Denmark and the Baltic coasts.
These invaders were succeeded by a second wave of Celtic-speaking peoples, the Cymry or Brythons, who drove their Goidelic predecessors still farther westward and exterminated and absorbed them over large areas. These Cymric invasions occurred about 300–100 B. C. and were probably the result of the growing development of the Teutons and their final expulsion of the Celtic-speaking tribes from Germany. These Cymry occupied northern France under the name of Belgæ and invaded England as Brythons in several waves, the last being the true Belgæ. The conquests of these Cymric tribes in both Gaul and Britain were only checked by the legions of Rome.
These migrations are exceedingly hard to trace because of the confusion caused by the fact that Celtic speech is now found on the lips of populations in nowise related to the Nordics who first introduced it. But one fact stands out clearly, all the original Celtic-speaking tribes were Nordic.
What were the special physical characters of these tribes in which they differed from their Teutonic successors is now impossible to say, beyond the possible suggestion that in the British Isles the Scottish and Irish populations in which red hair and gray or green eyes are abundant have rather more of this Celtic strain in them than have the flaxen haired Teutons, whose china-blue eyes are clearly not Celtic.