For the last fifteen hundred years the Celtic tongues have been spoken only in the extreme north-west of Europe, in parts of Ireland, the west of Scotland, and the Isle of Man, in Wales, Cornwall and Brittany, and for some little time these languages have ceased to be spoken in Cornwall and the Isle of Man. But we have ample evidence that these tongues had once a wider range, and were pushed westward in the first instance by the spread of Roman culture and the Latin language as the empire increased its bounds, and still more by the Teutonic tribes who invaded the western half of that empire and brought about its fall. If however we examine the evidence which has come down to us from the first century before the Christian era, especially such material as has been furnished by Cæsar and Strabo, we shall find that languages of the Celtic type were spoken at that time throughout all Europe west of the Rhine and north of the Pyrenees and the southern slopes of the Alps. We shall note also that these tongues were spoken in many parts of Spain and in North Italy, though in both these areas they were of relatively late introduction. Again there is another area in which Celtic speech was in use at that time, or had been shortly before. This is the mountain or Alpine zone of Central Europe, as far east, at least, as a line drawn from Cracow to Agram. It is possible, too, that such tongues may have been spoken at one time still further east. The problem before us is to inquire first in what region the Celtic tongues originated, then how and when they spread to the areas in which we find them two thousand years ago. To do this we shall have to review the condition of these areas both from the standpoint of prehistoric archæology and physical anthropology, to see whether the evidence derived from these sciences, taken together with that drawn from comparative philology and the study of place-names, can help us to reach a solution. But the problem is further complicated by the fact that the Celtic languages fall into two groups. In the one occurs the sound _qu_, which has in later days become a hard _c_, while in the other this sound has become labialised and converted into a _p_ or _b_. It has been thought by some that the _qu_ peoples, spoken of usually as Goidels or Gaels, arrived first from the common Celtic home, and that the _p_ peoples, called Brythons or Cymri, came later from the same centre; this view is, however, strenuously denied by others. We have, therefore, to determine if we can, not only whence and when the Celtic languages arrived in the west, but whether they came in one, two or more waves. [Illustration: FIG. 1.--CELTIC LANDS AND THE CELTIC CRADLE.]