This demand of the Tuatha Dé Danann led to the First Battle of Moy Tura in which the Tuatha Dé defeated the Fir Bolg and Nuada, King of the Tuatha De, lost an arm and because of this mutilation was obliged to abdicate in favour of Breas the Beautiful.

Breas was a tyrannical ruler. His race laboured under heavy taxation demanded by their ancient adversaries the Fomor. Moreover Breas lacked the mark of a true king of his race: generosity. The chieftains of the Tuatha Dé complained that "their knives were not greased by him, and however often they visited him their breaths did not smell of ale." "There was no art, no music, no poetry, no entertainment; Ireland was a "land of sheep" and the Tuatha Dé were divided.

Meanwhile Nuada, his arm struck off, was seven years under cure from Dian Cécht the Healer. During this time the healing was completed and a silver arm, richly decorated with sacred runes, and with movement in every finger, was fitted to his shoulder. From that time on he was known as Nuada Airgedlámh, or Nuada of the Silver Arm, and he was reinstated in the Sovereignty.

With the help of Lugh the Il-Dána, the greatest hero and champion of the Tuatha Dé Danann and led by their king, Nuada of the Silver Arm, the Tuatha De defeated the Fomor in the Second Battle of Moy Tura. However, while they were victorious over their age-old enemies the price they paid was high: many of their warriors, champions and chieftains were slain, including Nuada, their King.

According to Lebor Gabála Nuada was slain by Balor of the Evil Eye while Balor himself lost his life to Lugh the Il-Dána, his own grandson in whim "all the blood of the races of Ireland were mixed."