This thesis has been severely attacked, especially by Peisker.[210] Still, though Huntington’s conclusions may require modification in detail, his main contention seems to have withstood the attacks made upon it. Mr. Brooks[211] has recently shown us that the climate of Europe has passed through considerable changes since the ice age, and that such changes come down to relatively recent times and may yet be in progress. He attributes these largely to changes in coast line, and to the relative masses of land and water. The Pumpelly reports[212] show that considerable changes of level have taken place in Turkestan, and but small changes are needed to connect the Aralo-Caspian basin, by means of the Obi valley, with the Arctic Ocean. All this tends to show that we may expect considerable variation in the climate of this region, while Huntington’s evidence of changes in the level of the Caspian Sea seems to prove that such variations have not been always in the same direction. Mr. Cook is, however, inclined to see in this the destruction of forests and their conversion into grass-lands by the primitive process of cultivation which he terms Milpa agriculture.[213]
It is to periods of light rainfall that Huntington attributes the four great irruptions from the Arabian desert which have been recognised by Semitic scholars,[214] the last of which spread the doctrine of Islam over the Near East; to the same cause he attributes, too, the various movements of the Huns and Tartars. One may reasonably add to this that even one dry year during the period of light rainfall may be sufficient to account for such an exodus.
Now, as I have endeavoured to show on a previous occasion,[215] such a period of light rainfall seems to have occurred between 2400 and 2200 B.C., though it may have been of somewhat longer duration. I further gave reason for believing that about 2225 B.C., or perhaps a little earlier, an invasion of nomads took place from the Russian steppes. It would seem that about this time the Tripolje culture came suddenly to an end, and from the evidence at Khalepje,[216] Minns was inclined to believe that it had been destroyed by the steppe-folk, who had buried one of their dead on the site formerly occupied by a Tripolje “area.” This destruction has recently been questioned, and it has been suggested that the Tripolje people may have abandoned this region, driven out rather by drought than by the attacks of the steppe-folk.
Be this as it may, for further excavations are needed before the question can be determined, there is no doubt that these nomads disappeared from the steppe for a time and were found in the Tripolje region. Further we have evidence that a people resembling them appeared soon afterwards in Thessaly, bringing with them pottery which appears to be derived from that of the Tripolje culture.[217] Others of this type seem to have been responsible for the destruction of Hissarlik II.,[218] while pottery, which also shows affinities with that of Tripolje, occurs later at Hissarlik and at Yortan on the Caicus.[219] Moreover, the kurgans, characteristic of these steppe-folk, have been found all over Thrace and even over Asia Minor from the Hellespont southwards to Lydia and Caria, as well as eastwards up the Sangarius into the plateau of Phrygia.[220] Thus we seem to be dealing with an advance of a steppe people, comparable with the various irruptions from the Arabian desert which did so much to change the course of history in Mesopotamia, and destroyed the Old and Middle Kingdoms in Egypt.
A further corroboration comes from Turkestan, from the mounds of Anau. In the south kurgan, the lower layers belonged to the period known as Anau III., which contained a copper culture and a three-sided seal,[221] which Mrs. Hawes recognised as having Middle Minoan affinities.[222] This settlement, which seems to have been in touch with the Elamite culture of Susa,[223] came suddenly to an end at a date which Pumpelly fixes at about 2200 B.C.[224] Whether the settlement was destroyed or merely abandoned is not quite clear, but what is important for our purpose is that two agricultural communities on the edge of the steppe, those of Tripolje and Anau, came to an end at exactly or almost exactly the same date.
I have also suggested[225] that in this last case we may perhaps see some proof of an hypothesis, advanced many years ago from legendary and linguistic data by Terrien de Lacouperie.[226] This ingenious author, who had been dead many years before the discoveries at Anau were made, suggested that certain tribes, settled near the Caspian Sea, whom he called the Bak tribes and who had been under the influence of the kings of Elam, left their settlements about 2200 B.C., and set out on a long trek towards China, into which land they introduced the beginnings of culture and the germs of the Chinese script.
This hypothesis was badly received when it appeared. Few of its critics had taken the trouble to master Lacouperie’s argument, which was advanced in a most confused style. Sir Robert Douglas,[227] however, a sinologist of no mean reputation, believed that there was a considerable amount of truth at the bottom of it, though the theory was overlaid by many fanciful conjectures. Recently M. Cordier[228] has dismissed the whole idea as imaginary and based on inaccurate linguistic data. The question, I venture to think, needs re-examination, for at Anau we find a settlement of peasants, in touch with the Elamites, abandoning their village just at the date suggested by Lacouperie.
All this evidence seems to point to the fact that owing to drought, either of a prolonged order or lasting for two or three consecutive summers, our steppe-folk, who buried their dead in a contracted position covered with red ochre, suddenly left the steppe lands between the Dnieper and the Asiatic frontier, and dispersed in search of wetter regions and richer pastures. Two settled agricultural civilisations on their borders, the Tripolje settlements in the Ukraine and those at Anau, disappeared at the same time, driven out either by the drought or by the advancing hordes.
That some went to the east as well as to the west seems probable, for we find not long afterwards, in the reign of Hammurabi, 2123–2061 B.C., bands of steppe-folk on the Iranian plateau, who had already tamed the horse.[229] These entered Mesopotamia and established the Kassite dynasty about 1760 B.C.,[230] and were the first to introduce the horse into the valley of the Tigris.[231] Whether or no other bands passed further to the eastward we have no positive evidence, but, as we have seen, there seem to be reasons for suspecting that some reached Tobolsk,[232] and there were at one time fair people dwelling in the upper basin of the Yenesei[233]. It seems probable that it is to this period that we must attribute this easterly movement. As it seems probable that the Mitanni barons, who were lording it over eastern Armenia, were of the same stock as the Kassites, we may attribute their arrival south of the Caspian to the same causes. Geographical considerations, too, would lead us to suspect that ample pasturage could have been found also among the hills surrounding Balkh.