The Milesians
King Milesius’ sons, Eremon and Eber, are said to have come from either Spain or France to the island of Ireland, and were ancestors of the Gaels. Of the Milesians, who invaded the Tuatha De Danann lands, Eber and Eremon divided the land between them – Eremon getting the Northern half of the Island, and Eber the Southern. The Northeastern corner was accorded to the children of their lost brother, Ir, and the Southwestern corner to their cousin Lughaid, the son of Ith.
Source: http://www.vretail.com/history.htm
The descendants of Milesius are said to be the monarchs and leading families of early Ireland.