This prophecy of the Christ, if indeed this is what it is, was first written down in the seventh century AD, at a time when Ireland and most of Britain was pagan.
The ancient Bards, the Druids, handed down verbally their tales, poems and laws.
This prophecy below is from the Voyage of Bran.
There are a large number of forms of the Voyage of Bran, but the oldest as any are to be found in the Würzburg glosses. The oldest part of these glosses, Professor Thurneysen, the most careful and cool-headed of observers, does not hesitate to ascribe to the seventh century.
As may be expected many of the words are seventh century, to which the ms can be dated to, but, some are borrowed from a much earlier time, the period of the first contact of the Irish with Roman civilisation, before the introduction of Christianity.
That the Christ was prophesised to the Gentile nations is known, as the Wise Men in Matthew chapter two confirms. The first prophecy of Christ is found in Genesis 3:15.
The translations below are in modern English.
A great birth will
come after ages,
That will not be in a lofty place,
The son of a woman whose mate will not be known,
He will seize the rule of the many thousands.
A rule without beginning, without end,
He has created the world so that it is perfect,
Whose are earth and sea,
Woe to him that shall be under His unwill!
Tis He that made the heavens,
Happy he that has a white heart,
He will purify hosts under pure water,
Tis He that will heal your sicknesses.
The pagan Celtic god Manannan is reputed to have said of the fall and future salvation:
A noble salvation will come. From the King who has created us, a white law will come over the seas, besides being God, He will be man.
We owe much to the Catholic scribes and poets of early mediaeval Ireland and Wales, who wrote down the mythic tales and legends of the heathen era, thus, preserving them for us. These had been passed down over centuries through the bards and that they were saved from destruction is due to the fact that Celtic Ireland and Wales was never Romanised, which happened in Europe and what is now England.