Atop a hill in Cornwall lie the remains of Castle Dore (possibly from d’or, or "gold"), built probably in the third century b.c., and occupied and fortified by the Britons during the post-Roman period.

Nearby, the Tristan Stone is found, which is a monument to "Drustanus" (Tristan), son of "Cunomorus". Cunomorus, a sixth-century Cornish king, may have lived in the castle. Cunomorus, furthermore, is identified with King Mark in the Life of St. Paul Aurelian.

This is said to read Drustans hic iacit cunomori filius - 'Here lies Tristan, son of Cunomorus'. If this is indeed the true meaning of the inscription, it would seem to imply that the relationship between King Mark and Tristan was far closer than later writers were prepared to allow.