This Ogam was apparently readable only by the initiated, for the prince did not himself know what he was bearing on his shield. All ancient Irish literature, then, is unanimous in attributing a knowledge of Ogam to the pre-Christian Irish. M. d'Arbois de Jubainville seems also to believe in its pagan antiquity, for when discussing the story of St. Patrick's setting a Latin alphabet before Fiach, and of the youth's learning to read the Psalms within the following four-and-twenty hours, he remarks that the story is just possible since Fiach should have known the Ogam alphabet, and except for the form of the letters it and the Latin alphabet were the same.[12] St. Patrick, too, tells us in his "Confession" how after his flight from Ireland he saw a man coming as it were from that country with innumerable letters, a dream that would scarcely have visited him had he known that there was no one in Ireland who could write letters.[13] The Ogam alphabet, however, is based upon the Roman. Of this there can be no doubt, for it contains letters which, according to the key, represents Q (made by five upright strokes above the stem line), Z, and Y, none of which letters are used in even the oldest MSS., and two of which at least must have been borrowed from the Romans. The most, then, that can at present be said with absolute certainty is, as Dr. Whitley Stokes cautiously puts it, that these Ogam inscriptions and the language in which they are couched are "enough to show that some of the Celts of these islands wrote their language before the fifth century, the time at which Christianity is supposed to have been introduced into Ireland."[14] The presence of these Roman letters never used by the Irish on vellum, and the absence of any aspirated letters (which abound even in the oldest vellum MSS.) are additional proofs of the antiquity of the Ogam alphabet. The Irish themselves ascribed the invention of Ogam to [the god] Ogma, one of the leading Tuatha De Danann,[15] and although it may be, as Rhys points out, philologically unsound to derive Ogam from Ogma, yet there appears to be an intimate connection between the two words, and Ogma may well be derived from Ogam, which in its early stage may have meant fluency or learning rather than letters. Certainly there cannot be any doubt that Ogma, the Tuatha De Danann, was the same as the Gaulish god Ogmios of whom Lucian, that pleasantest of Hellenes, gives us an account so delightfully graphic that it is worth repeating in its entirety as another proof of what I shall have more to speak about later on, the solidarity--to use a useful Gallicism--of the Irish and the Continental Gauls.