Taliesin ( , ; 6th century AD) was an early Brittonic poet of Sub-Roman Britain whose work has possibly survived in a Middle Welsh manuscript, the ''Book of Taliesin''. Taliesin was a renowned bard who is believed to have sung at the courts of at least three kings.

In 1960, Ifor Williams identified eleven of the medieval poems ascribed to Taliesin as possibly originating as early as the sixth century, and so possibly being composed by a historical Taliesin. The bulk of this work praises King Urien of Rheged and his son Owain mab Urien, although several of the poems indicate that Taliesin also served as court bard to King Brochfael Ysgithrog of Powys and his successor Cynan Garwyn, either before or during his time at Urien's court. Some of the events to which the poems refer, such as the Battle of Arfderydd (), are referred to in other sources. John T. Koch argues that the description of Easter in the praise poem ''Yspeil Taliesin'' ('The Spoils of Taliesin') indicates that Urien and Taliesin were Christians who adhered to the Latin rather than the Insular observance of Easter. He also suggests that the figure of Taliesin served as a bridge between the worlds of Brittonic Christian Latin literature and the Heroic Age court poets, allowing monastic scribes to cultivate vernacular poetry.

In legend and medieval Welsh poetry, he is often referred to as ''Taliesin Ben Beirdd'' ("Taliesin, Chief of Bards" or chief of poets). He is mentioned as one of the five British poets of renown, along with Talhaearn Tad Awen ("Talhaearn Father of the Muse"), Aneirin, Blwchfardd, and Cian Gwenith Gwawd ("Cian Wheat of Song"), in the ''Historia Brittonum'', and is also mentioned in the collection of poems known as ''Y Gododdin''. Taliesin was highly regarded in the mid-12th century as the supposed author of a great number of romantic legends.

According to legend Taliesin was adopted as a child by Elffin, the son of Gwyddno Garanhir, and prophesied the death of Maelgwn Gwynedd from the Yellow Plague. In later stories he became a mythic hero, companion of Bran the Blessed and King Arthur. His legendary biography is found in several late renderings (see below), the earliest surviving narrative being found in a manuscript chronicle of world history written by Elis Gruffydd in the 16th century. Provided by Wikipedia