And so it has happened. Of the three ancient names of Ireland—Banba, Fotla, and Eriu—the last, in its genitive form of “Erinn”, is the one that has survived.
The invaders came to Tara, then called Drumcain, that is, the “Beautiful Hill”. Mac Cuill, Mac Cecht, and Mac Greiné met them, with all the host of the Gaelic gods. As was usual, they held a parley. The people of the goddess Danu complained that they had been taken by surprise, and the Milesians admitted that to invade a country without having first warned its inhabitants was not strictly according to the courtesies of chivalrous warfare. The Tuatha Dé Danann proposed to the invaders that they should leave the island for three days, during which they themselves would decide whether to fight for their kingdom or to surrender it; but the Milesians did not care for this, for they knew that, as soon as they were out of the island, the Tuatha Dé Danann would oppose them with druidical enchantments, so that they would not be able to make a fresh landing. In the end, Mac Cuill, Mac Cecht, and Mac Greiné offered to submit the matter to the arbitration of Amergin, the Milesians’ own lawgiver, with the express stipulation that, if he gave an obviously partial judgment, he was to suffer death at their hands. Donn asked his druid if he were prepared to accept this very delicate duty. Amergin replied that he was, and at once delivered the first judgment pronounced by the Milesians in Ireland.
“The men whom we found dwelling in the land, to them is possession due by right.
It is therefore your duty to set out to sea over nine green waves;
And if you shall be able to effect a landing again in spite of them,
You are to engage them in battle, and I adjudge to you the land in which you found them living.
I adjudge to you the land wherein you found them dwelling, by the right of battle.
But although you may desire the land which these people possess, yet yours is the duty to show them justice.
I forbid you from injustice to those you have found in the land, however you may desire to obtain it.”[[150]]
This judgment was considered fair by both parties. The Milesians retired to their ships, and waited at a distance of nine waves’ length from the land until the signal was given to attack, while the Tuatha Dé Danann, drawn up upon the beach, were ready with their druidical spells to oppose them.