The cairns on Carn Gafallt are likely to be bronze age*, based on the fact that four middle-bronze-age gold torcs were found on the hill under one of the lesser stone-piles which litter the area*. In addition, their general form (stone cairns) and location (near a hilltop) suggests a bronze age - for other examples from Wales, see Browne and Hughes*. Arthur, however, such as he is, is largely regarded as a Dark Age hero - at best (if we ignore the earliest written sources and wildly speculate) extending back to the Romano-British or Iron Age.