Who were the Celts?

According to Irish myth and legend they were the sons of Miled who travelled from Spain. They were believed to be a completely human race of people, compared to the peoples before them who would have been of magical races. Through-out the various museums of Europe the Art of the Celts can still be seen.
The story goes that Mileds grandfather Ith from his tall tower saw a land far off in the western horizon and decided he must sail to it. On reaching the island of Ireland, Ith along with ninety of his warriors were greeted by the sons of a Tuatha De Dannan king Neit. Neit had been killed in the battle between the Tuatha De Dannan and the fomorians.  
MacCuill, MacCecht and MacGrene were in disagreement with each other when Ith landed. They asked Ith to settle their inheritance after their fathers death. Ith as well as giving his Judgement he tells them of his admiration of Irelands green and fertile land. The three De Dannans take Iths admiration with suspision, thinking that he had higher plans to take their country Ith was put to death. His body was recovered and brought back to Spain. Mileds sons vowed to take revenge and began preparing for the invasion of the far off island.
On the way to Ireland one of Mileds sons fell from the mast of a ship and was drowned, also Amergins wife Sceine died on the journey and was buried at Inbhear Sceine or Kenmare bay in County Kerry. Amergin the poet son of Miled invokes the land of Erin stating that he is the wind, water, bull, hawk, flower, salmon, lake, and hill.
The Milesian army after landing travelled to Tara  where they meet the three kings of the Tuatha De Dannan and demanded control of the country. The three kings ask for three days to decide and that the Milesians should retreat to the sea and return not having the advantage of surprise. The Milesians agree and sail nine waves from Irelands shore.

It was at the Hill of Taillte in county Meath where a great battle was to follow. At the battle the three sons of Neit, MacCuill, MacCecht and MacGrene along with their wifes Banba, Fodla, and Eriu and their children were killed. With the Tuatha De Dannan routed the Milesians took control of the Country. Ireland was then divided between two of the sons of Miled, Eireamhon ruling in the North and Eibhear in the South.