 Set into the lower slope of the hillfort is an early-Christian memorial stone known as the ″Cunaide Stone″, which was discovered in 1843.Research on the inscription suggests it dates to the 5th-century AD, has European inspiration and the name is possibly Irish in origin.Religion and trade continued during the early medieval period with pilgrimages to St Michael's Mount and European shrines, but trade declined during the later medieval period when the estuary became choked by silt due to tin extraction up river.