In dealing with the deities of the Celtic world we must not, however, forget the goddesses, though their history presents several problems of great difficulty. Of these goddesses some are known to us by groups--Proximae (the kinswomen), Dervonnae (the oak-spirits), Niskai (the water-sprites), Mairae, Matronae, Matres or Matrae (the mothers), Quadriviae (the goddesses of cross roads). The Matres, Matrae, and Matronae are often qualified by some local name. Deities of this type appear to have been popular in Britain, in the neighbourhood of Cologne and in Provence. In some cases it is uncertain whether some of these grouped goddesses are Celtic or Teutonic. It is an interesting parallel to the existence of these grouped goddesses, when we find that in some parts of Wales 'Y Mamau' (the mothers) is the name for the fairies. These grouped goddesses take us back to one of the most interesting stages in the early Celtic religion, when the earth-spirits or the corn-spirits had not yet been completely individualised. Of the individualised goddesses many are strictly local, being the names of springs or rivers. Others, again, appear to have emerged into greater individual prominence, and of these we find several associated on inscriptions, sometimes with a god of Celtic name, but sometimes with his Latin counterpart. It is by no means certain that the names so linked together were thus associated in early times, and the fashion may have been a later one, which, like other fashions, spread after it had once begun. The relationship in some cases may have been regarded as that of mother and son, in others that of brother and sister, in others that of husband and wife, the data are not adequate for the final decision of the question. Of these associated pairs the following may be noted, Mercurius and Rosmerta, Mercurius and Dirona, Grannus (Apollo) and Sirona, Sucellus and Nantosvelta, Borvo and Damona, Cicolluis (Mars) and Litavis, Bormanus and Bormana, Savus and Adsalluta, Mars and Nemetona. One of these names, Sirona, probably meant the long-lived one, and was applied to the earth-mother. In Welsh one or two names have survived which, by their structure, appear to have been ancient names of goddesses; these are Rhiannon (Rigantona, the great queen), and Modron (Matrona, the great mother). The other British deities will be more fully treated by another writer in this series in a work on the ancient mythology of the British Isles. It is enough to say that research tends more and more to confirm the view that the key to the history of the Celtic deities is the realisation of the local character of the vast majority of them. CHAPTER VI--THE CELTIC PRIESTHOOD