Caerleon is called "City of the Legions" by Geoffrey of Monmouth. He tells how Arthur holds court there and it remains an Arthurian center, never fully eclipsed by Camelot. Caerleon was also the closest place to Geoffrey's home town of Monmouth with ancient ruins of any note. Geoffrey also makes Caerleon the location of Guinevere's convent.
Before modern excavation, the amphitheater was covered by earth that followed the building's oval shape and local legend held that this was the true Round Table. There is also a local variant of the Arthur's Cave legend that tells of an underground chamber in a wood where one thousand of Arthur's men sleep until they are needed by Wales.