"Amergin" is the word as it has been written in English, but the actual spelling of this name is "Amhairghin". It means "Birth of Song".

And according to legend, Amhairghin was one of the leaders of the "Men of Míl", who battled the Tuatha Dé Danann (or the Faery Clan) for possession of Ireland. As you can see for yourself, the Song of Amergin is, in itself, a self-claiming by Amergin of this island, as well as a challenge to the Tuatha Dé Danann, who were considered to be the gods.

Amergin's invokes the powers of the Land here upon first stepping ashore in Ireland. These words came from Amergin's "imbas" ('poetic inspiration') and they marked the start of battle over sovereignty of the Land. With the words of this poem, Amergin claims the elements of Ireland. This gesture displays his Otherworldly wisdom and power over the elements. Here, he is actually "becoming"... all of these elements, or "duile" as they were called by the Druids. He joins himself (his "Fein" and internal "duile") with the spirit that controls the elements of the Cosmos. This could be looked upon as merely symbolic, but however you wish to see it, it got results. The wind died down and the Gaels claimed sovereignty on Ireland .

This piece of work has been translated by many and probably misinterpreted by a few, but here is one version that I have found, and hopefully retained from a reliable source.