Always remember to respect a Bard...

Nuada was the first king of the Tuatha Dé Danann, who brought his tribe to Ireland and contended with its inhabitants for possession of the island. At the first battle at Mag Tuireadh, Nuada's warriors clash with the Fir Bolg. The battle is carried out as a series of single combats, one warrior against another, until Nuada is matched with a Fir Bolg champion, Streng. Nuada fights fiercely, but he suffers a great loss — the enemy warrior slices off his left hand at the wrist. Even so, the Fir Bolg are eventually driven back, and they retreat to the western province of Connacht.

Because sacred law decrees that a king of the Dé Danann must be whole in body and mind, the maimed Nuada is forced to step down as ruler of the gods. A council is convened, and a new king is appointed by vote, a half-Fomorian named Bres the Beautiful. . Unlike the rather conventional Fir Bolgs, the Fomorians are, like the Dé Dananns, a magical race, described as misshapen one-eyed giants who live under the waves.  However, Bres gets to be King because he is not misshapen like the others. 

Bres, despite his dashing figure, proves a very unpopular king. He identifies with his Fomorian side and treats the Dé Dananns terribly, levying large taxes and forgoing the usual hospitality and entertainments a king is expected to provide. A solution is sought, and finally, the Dé Danann Lugh uses his healing skill to fashion for Nuada a fantastic silver hand, which functions as well as a human hand. Restored to wholeness, Nuada seeks to regain his position.

Bres, however, is having none of it. He enjoys being king and naturally refuses to step aside. All seems hopeless until a bard, Cairpre, seeks the hospitality of Bres' court and, like so many before him, is refused. The offended Cairpre composes the first bardic satire (satire is when someone uses jokes to point out another's shortcomings) of legend, a scathing indictment of Bres's stinginess:

No meat on the plates; No milk of the cows; No shelter after sunset; No money for minstrels: May Bres's cheer be what he gives others!

In other words, the Bard is saying he hopes the king gets the same treatment he gives to others.  The poem embarrasses Bres so greatly that his face breaks out in gigantic boils, a disfiguration great enough to force Bres to abdicate the throne according to the ancient rules. In short order, Nuada is once again king of the Tuatha Dé Danann.

The dethroned Bres has no intention of going quietly. He complains of his humiliation to his Fomorian relatives, and the Tuatha Dé Danann soon face a wave of invaders.  But, they will stand with greatness!