Leslie Grinsell reported from Hogg’s 1975 ‘Hillforts of Britain’, that:
“Within the Early Iron Age defences are the foundations of an early medieval castle which could well have belonged to Macbeth.”
‘Could well have belonged’ eh.
Notes on the Folklore of Prehistoric Sites in Britain
L. V. Grinsell
Folklore, Vol. 90, No. 1. (1979), pp. 66-70.