Gwytheon is the legendary Sonaide Bri bard who composed The Ádairiad, a collection of poems about the reign of the legendary King Ádair ap Uedán millennia ago.
By his own accounts, Gwytheon was not present when Ádair was presented to the petty kings as anointed by the Áes Camáir gods to be their High King, evidenced by the holy relics Fáebar dé Gérat and Lía dé Ordae that they presented to him. Nor was he present for the Goblin Wars, nor for the construction of the principle fortress at the heart of Ádair’s castle Trevena, nor Ádair’s marriage to Queen Whenfara.
Gwytheon did not personally appear at Trevena until at least fifteen years after Ádair’s coronation and a decade after his marriage.
In The Fall of Trevena, the final saga of The Adairiad, Gwytheon describes how he aided in the evacuation of Trevena, helping bring Ádair and Whenfara’s twin children to safety with their nurse and a retinue of knights to protect them. He then returned to Trevena, where he saw smoke and flashes of lightning while he was still miles away. Using his arts, he scried upon the palace and was able to see King Ádair and the trusty mage Myogan locked in battle with the demon Baylígûr. Then the walls of the castle came crashing down, killing all who remained within.
The sight drove Gwytheon mad for a time, and he wandered through the forests for a year and a day, crying out in either gibberish or a strange tongue that none could understand. On the day that he came out of his madness, the Four Winds appeared before Gwytheon and presented him with The Óirlúit, a magical harp of immense power, that he might use it to tell the tale of King Ádair and never let it be forgotten.