The medieval Irish Book of Invasions, an amalgam of bible and Irish lore, was considered to be the origin story of the Irish people. McAlister's definitive translation was compiled from several manuscripts dating from the 12th to 15th century, but textual analysis suggests dates the stories date earlier. The relevant passage on Nel and Moses describes how Nel and his son Gaedel Glas, having participated in the great Tower of Babel project, are retained by the Pharoah as tutors. Subsequent marvelous events are discussed in the Irish Book of Invasions as follows:
 
 

So Nel son of Feinius Farsaid dwelt southward in Egypt.

This is the estate which he received, upon the shores of the Red Sea, and around Phi- Hahiroth: and he was there till the Sons of Israel escaped from Pharao and from the host of Egypt.

Now it fell out that the Sons of Israel, in that flight, came to the estate where Nel was, and his son, Gaedel Glas.

The Sons of Israel took camp at Phi-Hahiroth, on the border of the Red Sea.

Then Nel son of Feinius came to converse with them: and there Aaron [brother of Abraham (sic)] met Nel; and Aaron told him tidings of the Sons of Israel, and the miracles and marvels of Moses, and how the ten plagues were brought upon the people of Egypt by reason of their enslavement.

And they ratified a friendship there, and Nel gives wine and wheat to the peoples of God for provision.

So Aaron went thereafter to the place where Moses was, and told him of the welcome which he had received at the hands of Nel, and the good which he promised to the Sons of Israel. Moses was grateful to Nel for that.

Now as for Nel, in that very night a serpent stung the little sone tht had been born to him, to wit Gaedel Glas, and death was near to him.

And the lad was carried to Moses, and Moses made fervent prayer before God, and put the noble rod upon the place where the serpent had stung him, so that the lad was cured. And thereafter Moses said:

I command, by the permission of God, that no serpent harm this lad, or any of his seed for ever; and that no serpent dwell in the homeland of his progeny.

There shall be, he said, kings and lords, saints and righteous, of the seed of this lad; and in the northern island of the world shall be the dwelling of his race.

This, then, is the reason why there are no serpents in Ireland, and why no serpent does harm to any of the seed of Gaedel Glas.

Then it is that Nel said: Pharao shall come to us, said he, and shall enslave us, for the welcome that we have given you, and for the guilt of failing to hinder you.

Come thou with us, said Moses, with all thy people, upon tomorrow's route, and if thou wilt, thou shalt receive an equal share of heritage in the land which God hath promised to the Sons of Israel.

Or, if thou dost perfer, we shall put the pinnaces of Pharao at thy disposal: embark ye therein upon the sea, and stand ye by, to know by what means we shall separate us from Pharao, and thereafter do thy good pleasure.

The company that was in the ships set forth and they stood by to see the transactions of the following day: the division of the Red Sea in the wake of the people, and the drowning of Pharao with his hosts therein-six score thousand footmen and fifty thousand horsemen, that is the tally which went to meet death, of the people of Pharao, in the Red Sea.

It was after this adventure that the tribe of wandering Gaels went to Spain, dwelling in the place now known as the province of Galicia, still to this day a stronghold of Gaelic music.