by Brian Edward Rise
An early Welsh saint whose Vitae ("Life") contains a legend wherein the saint is in possession of a magic floating altar. This altar floats down the Bristol Channel to Somerset in the vicinity of a castle belonging to Cato (Cadwy) and Arthur. Carranog cannot find the altar upon his arrival but he finds Arthur pursuing a great serpent. Arthur says he will tell Carannog where the altar is if he will defeat the serpent. The saint summons and banishes the giant snake, and Arthur produces the altar.
It seems that Arthur tried to keep it and use it for a table but the altar threw off anything that he placed on it.