He further pointed out that the Greek language, with certain exceptions, was a true P dialect, for the Latin _equus_ corresponded to the Greek ἱππὁς. He suggested, however, that the Ionic dialect used by Herodotus and Hippocrates, which frequently had a κ where the standard Greek had a π,[465] was a descendant of a form of Q speech, but that the Qu had degenerated into κ, as it had into C in Goidelic. Further, he pointed out that the Q dialects, Goidelic, Latin and Ionic Greek, formed so to speak an outer ring, while Brythonic, Umbrian and standard Greek lay within them. He argued from this that these tongues had spread in two waves from a common centre, which he fixed in the mountain zone of Central Europe, and thence the Q tongues had spread by invasion, to be followed some few centuries later by a second invasion of P people, who had driven the Q people further from the original home. He suggested that the change of Q into P had been effected by a conquering group of aliens, who had adopted the Wiro tongue from their subjects, but retained some details of the phonological laws of their original language, which accounted for this labialisation. He further suggested that these alien invaders were the Alpine inhabitants of the Swiss lake-dwellings.[466] This paper was received with hostile criticism and derision, especially by some German students of Celtic tongues.[467] It had little better reception in France, and the British and Irish Celtic scholars, with a few exceptions, treated the idea with contempt. The theory has never received the consideration and fair criticism which a paper from so eminent an authority on Celtic languages deserved. The main facts as to the Celtic and Italic dialects are not in dispute. There can be no question that in both of those areas both Q and P groups are or were in existence, and that the Q are in the outer and the P in the inner ring. With regard to Greek however, the case is different, and it is generally considered that the dialect of Herodotus and Hippocrates is purely local and not necessarily primitive, and it has been pointed out that had the original Ionic dialect been a Q tongue, signs of this would have been apparent in Homer. It is also becoming more common to consider Greek as having closer affinities with Persian than with Italic or Celtic, though one wonders whether this connection is not being exaggerated as the pendulum swings from the over-estimated resemblance formerly recognised between the two languages of the Classical world.