At one time in the remote past, in the Neolithic Age, that is to say 6000[80] years or more ago, there may have been one simple original speech from which all these Aryan languages have differentiated. Somewhere between central Europe and western Asia there must have wandered a number of tribes sufficiently intermingled to develop and use one tongue. It is convenient here to call them the Aryan peoples. Sir H. H. Johnston has called them “Aryan Russians.” They belonged mostly to the Caucasian group of races and to the blond and northern subdivision of the group, to the Nordic race that is. Here one must sound a note of warning. There was a time when the philologists were disposed to confuse languages and races, and to suppose that people who once all spoke the same tongue must be all of the same blood. That, however, is not the case, as the reader will understand if he will think of the negroes of the United States who now all speak English, or of the Irish, who--except for purposes of political demonstration--no longer speak the old Erse language but English, or of the Cornish people, who have lost their ancient Keltic speech. But what a common language does do, is to show that a common intercourse has existed, and the possibility of intermixture; and if it does not point to a common origin, it points at least to a common future. But even this original Aryan language, which was a spoken speech perhaps 4000 or 3000 B.C., was by no means a _primordial_ language or the language of a savage race. Its speakers were in or past the Neolithic stage of civilization. It had grammatical forms and verbal devices of some complexity. The vanished methods of expression of the later Palæolithic peoples, of the Azilians, or of the early Neolithic kitchen-midden people for instance, were probably much cruder than the most elementary form of Aryan. Probably the Aryan group of languages became distinct in a wide region of which the Danube, Dnieper, Don, and Volga were the main rivers, a region that extended eastward beyond the Ural mountains north of the Caspian Sea. The area over which the Aryan speakers roamed probably did not for a long time reach to the Atlantic or to the south of the Black Sea beyond Asia Minor. There was no effectual separation of Europe from Asia then at the Bosphorus.[81] The Danube flowed eastward to a great sea that extended across the Volga region of south-eastern Russia right into Turkestan, and included the Black, Caspian, and Aral Seas of to-day. Perhaps it sent out arms to the Arctic Ocean. It must have been a pretty effective barrier between the Aryan speakers and the people in north-eastern Asia. South of this sea stretched a continuous shore from the Balkans to Afghanistan.[82] North-west of it a region of swamps and lagoons reached to the Baltic. § 3