The first stories we have of the history of Ireland from Ireland itself are those of the Tuatha de Danaan, the people or gods as they were of Dana. The following is the myth of how the Tuatha came to inhabit Ireland.
Now, there were people living there before the Tuatha. The first people to Ireland were the Fomorians, a demonic race who ravaged the land. Then came the Parthalonians who drove off the Fomorians only to see himself and all his people except Tuan die of plague. Tuan lived to see the next invaders. The Nemedians, who came, defeated the Fomorians but were then ravaged by plague, and wiped out by the remaining Fomorians. Tuan still alive turned into a wild boar and saw the arrival of the Firbolgs. The Firbolgs lived and fed off the land until Tuan turned into an eagle to witness the arrival of the Tuatha de Danaan. The Tuatha came with the wind on the first of May, the day of Beltaine. They came from the north from a place with four great cities of learning and brought with them four sacred objects from those cities. The first was a Stone of Virtue called the Lia Fail from Falias. Next they brought the Stone of Destiny, a Sword from Gorias, a Spear of Victory from Finias, and a Cauldron from Murias from which none would walk away hungry.
They landed at Connacht and there began to settle. The Firbolgs were told of the arrival of the Tuatha and sent their best warrior out to talk to them, Sreng. The Tuatha being alerted by scouts of this man sent out one of their own champions, Bres. The two met and Bres began to speak in his Irish tongue. Sreng seeing this man was also Irish became less hostile and the two quickly became comfortable talking to each other. Bres told Sreng of his peoples demands of half of Ireland in peace. Sreng agreed to tell his people but on one condition. They still remain friends. So with this they parted and told their peoples of their encounters. The Firbolgs quickly began for battle with the Tuatha because they refused to give up half of Ireland.
Thus, the Tuatha began to move on the Firbolgs. When they were closing in they had Badb, Macha, and the Morrigu raise a terrible storm of blood and fire over the Firbolg. The Firbolg had the enchantment broken by their Druids and the battle soon begun. The battle began on a Midsummer day and lasted for a total of four days. On the fourth day the Tuatha managed to kill the king of the Firbolgs, Eochaid, and stop the war with a truce and let the Firbolgs choose one of the five provinces in which to remain. They chose Connacht and their stayed.
During the battle Nuada, king of the Tuatha, lost his arm. Now it was a law that no man of imperfection could rule so the people chose Bres as their new leader and king. The years that followed were bad for the land and its people. The Fomorians imposed a tax on the Tuatha and Bres did nothing to help. Instead he imposed a tax on himself on the milk of the cows of Ireland. Meanwhile, Nuada was being healed by Diancecht who made him an arm of silver. His son, Macha, not being satisfied by his fathers work decided to take Nuadas old limb and put it back on and did so. Three days and three nights it took for it to heal but once done it was back to normal. Diancecht was jealous of his sons work and stuck him four different times till he died. Macha was buried and three hundred and sixty-five herbs grew above his grave and Airmed, his sister went out to pick them and her father seeing this mixed up the herbs so that no one to this day knows their right powers. When the Tuatha saw that Nuada was well they had Bres give up his throne and he left to the land of the Fomorians were his father was king. Once there he began to plan for the future.