The father of Declan was therefore Erc Mac Trein.

Through the grace of God, these, i.e. Erc and Deithin, believed in God and Colman, and they delivered the child for baptism to Colman who baptised him thereupon, giving him the name of Declan.

Erc he requested the latter and Deithin to give him the child to foster, and with this request Erc complied.

Erc he requested the latter and Deithin to give him the child to foster, and with this request Erc complied.

To the chief, Eocaid, Erc's son, came rumor of the strangers near the Lakes of Erne; their ships, burned at their debarking, were not there to tell of the manner of their coming, and the De Danaans themselves bruited it abroad that they had come hither by magic, borne upon the wings of the wind.

Eocaid, Erc's son, their chieftain, called the lesser chiefs around him, and Sreng made full report of what he had seen and heard.

Nuada, the De Danaan king, once more sought a peaceful issue to their meeting, but Erc's son Eocaid refused all terms, and it was plain to all that they must fight.

Great and dire was the slaughter of them, so that Erc's son Eocaid saw that all was lost.

At the very sea's margin a great battle was fought between the last king of the Firbolgs with his men, and the De Danaans under Nemed's sons; so relentless was the fight along the tideways that few remained to tell of it, for Erc's son Eocaid fell, but Nemed's three sons fell likewise, The three De Danaan brothers were buried at the western end of the strand, and the place was called The Gravestones of the Sons of Nemed, in their memory.

The son of Erc was buried on the strand, where the waves lap along the shore, and his cairn of Traig Eotaile still stands by the water-side, last resting-place of the last ruler of the Firbolgs.

To show how the old order continued with the new, we may record the words of the Chronicler for the following year: "526: The battle of Eiblinne, by Muirceartac son of Erc; the battle of Mag-Ailbe; the battle of Almain; the battle of Ceann-eic; the plundering of the Cliacs; and the battle of Eidne against the men of Connacht."

The mediaeval Chronicler quotes the old Annalist for the following year: "The king, the son of Erc, returned to the side of the descendants of Nial.