The word Celt itself is probably of very ancient origin, and was, no doubt, in use 800 or 1,000 years before Christ.[5] It cannot, however, be proved that it is a generic Celtic name for the Celtic race, and none of the present Celtic-speaking races have preserved it in their dialects. Jubainville derives it, very doubtfully I should think, from a Celtic root found in the old Irish verb "ar-CHELL-aim" ("I plunder") and the old substantive to-CHELL ("victory"); while he derives Galatian from a Celtic substantive now represented by the Irish gal[6] ("bravery"). This latter word "Galatian" is one which the German peoples never adopted, and it appears to have only come into use subsequently to their revolt against their Celtic masters. After the break-up of the Celtic Empire it was employed to designate the eastern portion of the race, while the inhabitants of Gaul were called Celtæ and those of Spain Celtici or Celtiberi, but the Greeks called all indifferently by the common name of Galatians.
The Romans termed the Celts Galli, or Gauls, but they used the geographical term Gallia, or Gaul, in a restricted sense, first for the country inhabited by the Celts in North Italy upon their own side of the Alps, and after that for the Celtic territory conquered by Rome upon the other side of the Alps.
The Germans appear to have called the Celts Wolah, a name derived from the Celtic tribe the Volcæ, who were so long their neighbours, out of which appellation came the Anglo-Saxon Wealh and the modern English "Welsh."
There is one curious characteristic distinguishing, from its very earliest appearance, the Celtic language from its Indo-European sisters: this is the loss of the letter p both at the beginning of a word and when it is placed between two vowels.[7] This dropping of the letter p had already given to the Celtic language a special character of its own, at the time when breaking forth from their earliest home the Celts crossed the Rhine and proceeded, perhaps a thousand years before Christ, to establish themselves in the British Isles. The Celts who first colonised Ireland said, for instance, atir for pater, but they had not yet experienced, nor did they ever experience, that curious linguistic change which at a later time is assumed to have come over the Celts of the Continent and caused them to not only recover their faculty of pronouncing p, but to actually change into a p the Indo-European guttural q. Their descendants, the modern Irish, to this very day retain the primitive word-forms which had their origin a thousand years before Christ. So much so is this the case that the Welsh antiquary Lhuyd, writing in the last century, asserted, and with truth, that there were "scarce any words in the Irish besides what are borrowed from the Latin or some other language that begin with p, insomuch that in an ancient alphabetical vocabulary I have by me, that letter is omitted."[8] Even with the introduction of Christianity and the knowledge of Latin the ancient Irish persisted in their repugnance to this letter, and made of the Latin Pasch-a (Easter) the word Cásg, and of the Latin purpur-a the Irish curcur.
But meantime the Continental Celts had either—as Jubainville seems to think—recovered their faculty for pronouncing p, or else—as Rhys believes—been overrun by other semi-Celts who, owing to some strong non-Aryan intermixture, found q repugnant to them, and changed it into p. This appears to have taken place prior to the year 500 B.C., for it was at about this time that they, having established themselves round the Seine and Loire and north of the Garonne, overran Spain, carrying everywhere with them this comparatively newly adopted p, as we can see by their tribal and place-names. They appeared in Italy sometime about 400 B.C.,[9] founded their colony in Galatia about 279 B.C., and afterwards sent another swarm into Great Britain, and to all these places they bore with them this obtrusive letter in place of the primitive q, the Irish alone resisting it, for the Irish represented a first off-shoot from the cradle of the race, an off-shoot which had left it at a time when q represented p, and not p q. Hence it is that Welsh is so full of the p sound which the primitive Irish would never adopt, as a glance at some of the commonest words in both languages will show.
| English: | Son | tree | head | person | worm | feather | everyone. |
| Welsh: | Map | prenn | pen | nep | pryv | pluv | paup. |
| Irish: | Mac | crann | cenn | nech | cruiv | cluv[10] | cách. |
So that even the Irish St. Ciaran becomes Piaran in Wales.[11]
The Celts invaded Italy about the year 400 B.C., and stormed Rome a few years later. They were at this time at the height of their power. From about the year 500 to 300 B.C. they appear to have possessed a very high degree of political unity, to have been led by a single king,[12] and to have followed with signal success a wise and consistent external policy. The most important events in their history during this period were the three successful wars which they waged—first against the Carthaginians, out of whose hands they wrested the peninsula of Spain; secondly in Italy against the Etruscans, which ended in their making themselves masters of the north of that country; and thirdly against the Illyrians along the Danube. All of these wars were followed by large accessions of territory. One of the most striking features of their external policy during this period was their close alliance with the Greeks, whose commercial rivalry with the Phœnicians naturally brought them into relations with the Celtic enemies of Carthaginian power in Spain, relations from which they reaped much advantage, since the necessity of making head against the Celtic invaders of Spain must have seriously crippled the Carthaginian power, at the very time when, as ally of the Persians, she attacked the Greeks in Sicily, and lost the battle of Himera on the same day that the Persians lost that of Salamis. Greek writers of the fourth century speak of the Celts as practising justice, of having nearly the same manners and customs as the Greeks, and they notice their hospitality to Grecian strangers.[13] Their war with the Etruscans in North Italy completed the ruin of an hereditary enemy of the Greeks,[14] and their war with the Illyrians no doubt largely strengthened the hands of Philip, the father of Alexander the Great, and enabled