Castle Dore occupies a position in the Cornish landscape near Golant and Fowey. Its earthworks include substantial banks and ditches surrounding an enclosure that once contained buildings. Radford's excavations in 1936 and 1937 uncovered evidence of round houses, pottery and more complicated groups of postholes. The Cornwall and Scilly Historic Environment Record places the settlement within the Iron Age, with some pottery assigned to the fifth or fourth century BCE. These remains establish a long-lived fortified settlement, not the identity of a particular Arthurian ruler or the historical truth of a romance.

The most influential interpretation concerned the postholes within the enclosure. Radford reconstructed a large timber hall and associated buildings that he believed belonged to the post-Roman period. This encouraged the identification of Castle Dore with the palace of King Mark. The later reassessment by Henrietta Quinnell and R. T. Harris, summarised in the Historic Environment Record, instead assigned the structural evidence to the Iron Age. The supposedly royal rectangular buildings could be granaries or other structures familiar at hillforts. No Roman or post-Roman finds were identified in that reassessment. The proposed palace must therefore be distinguished from the excavated evidence.

The nearby Tristan Stone carries an early medieval inscription recording Drustanus as the son of Cunomorus. Its name reflects the proposed connection between Drustanus and Tristan, while Cunomorus has been linked with King Mark through the broader Cornish and Breton tradition. Those connections are interpretations, not names supplied by the stone itself as a reference to the romance. Historic England records a range of proposed dates for the inscription rather than a universally agreed single year or century. The stone has also been moved, so its present position cannot by itself establish the original relationship between the memorial and the hillfort.

Literary geography adds another layer. The surviving Tristan poem of Béroul names Lancien as a setting associated with Mark, and scholars have proposed a connection with Lantyan in the Fowey area. Béroul's work survives as a fragment, not a complete version of the entire Tristan story, and a proposed place-name identification is not the same as his explicitly naming Castle Dore. The hillfort, the inscribed stone and the romance setting have nevertheless encouraged readers to imagine Tristan, Isolde and Mark within a shared Cornish landscape. Keeping these strands separate allows their connections to remain interesting without turning suggestion into proof.

Castle Dore acquired a further historical association during the campaign around Lostwithiel in 1644, when Parliamentary forces occupied the area. This military use belongs to a documented conflict centuries after the medieval romances, not to the Arthurian setting. The fort's place in that campaign adds a further layer of human use to the older earthworks. Castle Dore's significance rests on the coexistence of a surviving Iron Age monument, the history of its excavation, later military use and a powerful literary association. The real place is Historical; the identification as King Mark's palace remains unproven.