Bran is an ancient Welsh hero, the son of Llyr, and is sometimes portrayed as an ancestor of Arthur.
In some legends, Bran brought Christianity to Britain, earning him the name "Bran the Blessed," or "Bendigeid Vran." When Bran died, he asked for his head to be buried under Tower Hill in London, facing France. Bran was believed to have magical powers that would keep the country safe from invading Saxons so long as it remained buried. The legend then goes on to say that Arthur dug up Bran's head to assert his supremacy over Celtic superstition. This gesture is referred to as one of the three "unfortunate disclosures" of Britain, related in the Welsh Triad.
"Bran" means "the Raven," and some see the story of Arthur's death as a parallel to the legend of Bran. Some chronicles have Arthur being transformed into a raven. And Celtic lore tells of a "god asleep in a cave in a western island," which could apply both to the cave legends and Arthur's final voyage to the Isle of Avalon.
Another correlation is that Bran is thought by some to be an early Grail (or Fisher) King. Robert de Boron, in his version of the legend, names the Grail King Bron. The two share similar wounds, the Fisher King was wounded in the thigh and Bran in the foot:
Dinas Bran is said to be a model for the Grail Castle. Some stories say that the Grail is hidden beneath the castle, and that only a boy accompanied by a white dog with a silver eye can recover the treasure.
Bran was certainly an early British hero.
Characters from King Arthur's legends