The RT of King Arthur was first mentioned in the Roman de Brut (1155) by the Norman monk Wace (?1110-?1175). Here it was a physical object designed to ensure equality between all of the Knights. Later stories gave various versions of its seating capacity, ranging from 13 up to a startling 1600. One of the seats, the Siege Perilous, remained unclaimed and awaited the purest of knights; any others who sought to sit there would die. At length Galahad claimed it.
Legends vary about the RT's origin, but the chief story is that it was made by Merlin for Uther Pendragon and, after Uther's death, was inherited by Leodegrance, king of Cameliard, then came into Arthur's possession when he married Leodegrance's daughter Guinevere. Not all of Arthur's knights were also Knights of the RT: they had to earn that right through demonstrations of courage and valour – hence the many Quests. The principal Knights of the RT were Agravain, Bagdemagus, Bedivere, Bors, Dinadan, Gaheris, Galahad, Gawain, Lamorak, Lancelot, Mordred (Modred), Pelleas, Perceval, Sagremore, Tor, Tristan and Yvain.
The RT signified not only equality but unity. Hermetic interpretation of the RT was that it was an earthly representation of completeness, paralleling one on the spiritual plane. With Galahad's completion of the circle, the time was right for the Second Coming, presaged by the Holy Grail. The RT also represented the Order of Knights anointed by Arthur. This is what Edward III (reigned 1327-1377) imitated in 1348 when he created the Noble Order of the Garter as the highest order of knighthood. [MA]