Annales Cambriae in the context of "Myrddin Wyllt"

King Arthur (Welsh: Brenin Arthur; Cornish: Arthur Gernow; Breton: Roue Arzhur; French: Roi Arthur) was a legendary king of Britain. He is a folk hero and a central figure in the medieval literary tradition known as the Matter of Britain.

In Welsh sources, Arthur is portrayed as a leader of the post-Roman Britons in battles against the Anglo-Saxons in the late-5th and early-6th centuries. He first appears in two early medieval historical sources, the Annales Cambriae and the Historia Brittonum, but these date to 300 years after he is supposed to have lived, and most historians who study the period do not consider him a historical figure. His name also occurs in early Welsh poetic sources, such as Y Gododdin. The character developed through Welsh mythology, appearing either as a great warrior defending Britain from human and supernatural enemies or as a magical figure of folklore, and was sometimes associated with the Welsh otherworld Annwn.

Nennius – or Nemnius or Nemnivus – was a Welsh monk of the 9th century. He has traditionally been attributed with the authorship of the Historia Brittonum, based on the prologue affixed to that work. This attribution is widely considered a secondary (10th-century) tradition.

Nennius was a student of Elvodugus, commonly identified with the bishop Elfodd of Bangor who convinced British ecclesiastics to accept the Continental dating for Easter, and who died in 809 according to the Annales Cambriae.

Mordred or Modred (/ˈmɔːrdrɛd/ or /ˈmoʊdrɛd/; Welsh: Medraut or Medrawt) is a major figure in the legend of King Arthur. The earliest known mention of a possibly historical Medraut is in the Welsh chronicle Annales Cambriae, wherein he and Arthur are ambiguously associated with the Battle of Camlann in a brief entry for the year 537. Medraut's figure seemed to have been regarded positively in the early Welsh tradition and may have been related to that of Arthur's son. As Modredus, Mordred was depicted as Arthur's traitorous nephew and a legitimate son of King Lot in the pseudo-historical work Historia Regum Britanniae, which then served as the basis for the subsequent evolution of the legend from the 12th century. Later variants most often characterised Mordred as Arthur's villainous bastard son, born of an incestuous relationship with his half-sister, the queen of Lothian or Orkney named either Anna, Orcades, or Morgause. The accounts presented in the Historia and most other versions include Mordred's death at Camlann, typically in a final duel, during which he manages to mortally wound his own slayer, Arthur. Mordred is usually a brother or half-brother to Gawain; however, his other family relations, as well as his relationships with Arthur's wife Guinevere, vary greatly.

In a popular telling, originating from the French chivalric romances of the 13th century and made prominent today through its inclusion in Le Morte d'Arthur, Mordred is a power-hungry son of Arthur from the incest with Morgause, prophesied by Merlin and destined to bring Britain to ruin. He survives Arthur's attempt to get rid of him soon after his birth and, years later, joins his half-brothers Gawain, Agravain, Gaheris and Gareth in Arthur's fellowship of the Round Table as a young and immoral knight. Eventually, Mordred learns of his true parentage and becomes the main actor in Arthur's downfall. He helps Agravain to expose the illicit love affair between Guinevere and Lancelot and then takes advantage of the resulting civil war to make himself the high king of Britain, ultimately leading to both his own and Arthur's deaths in their battle. Today, he remains an iconic character in many modern adaptations of Arthurian legend, in which he usually appears as a villain and the archenemy of Arthur.

David (Welsh: Dewi Sant; Latin: Davidus; c. 500 – c. 589) was a Welsh Christian prelate who served as Bishop of Mynyw during the 6th century. He is the patron saint of Wales.

David was a native of Wales, and tradition has preserved a large amount of detail about his life. His birth date, however, is uncertain: suggestions range from 462 to 512. He is traditionally believed to be the son of Non and the grandson of Ceredig ap Cunedda, king of Ceredigion. The Welsh annals placed his death 569 years after the birth of Christ, but Phillimore's dating revised this to 601.