‘Llywarch the Aged’, ‘Llywarch the Old’
Glennie lists him as one of the four great bards of the Arthurian age. He was a celebrated Welsh poet who may have flourished about the year AD 600. He was said to have been a cousin of Urien of Rheged. He is sometimes, incorrectly, identified with Taliesin.
Traditions variously place him among the North Britons or in Powys. He may once have figured in independent tales but later been drawn into the Arthurian circle. One of Arthur’s three Counselor Knights, according to the Welsh Triads. He was so named because he gave precious advice to Arthur. In the Triads, he is also listed as one of the Three unrestricted guests and Three wanderers of Arthur’s court.
Llywarch has a larger role in non-Arthurian legend and history, where he is said to be the cousin and contemporary of Urien, a bard, and the father of twenty-four sons.
See also
Heledd | The Legend of King Arthur
Source
Triads of the Island of Britain (Welsh ”Triads”) | 11th century to 14th century