The Head of Bran the Blessed, son of Llyr, which was buried in the White Hill in London, and as long as the Head was there in that position, no Oppression would ever come to this Island; The second: the Bones of Gwerhefyr the Blessed which were buried in the Chief Ports of this Island; The third: the Dragons which Lludd son of Beli buried in Dinas Emrys in Eryri.
The text of the Early Version Triad is incomplete. The Red Book’s version includes the disclosures: the Bones (for the love of a woman) and the Dragons by Gwrtheyrn the Thin (Vortigen); the Head by Arthur because it did not seem right to him that this Island should be defended by the strength of anyone other than him.
Sources
Red Book of Hergest | C. 1425
Triads of the Island of Britain (Welsh ”Triads”) | 11th century to 14th century