The Three Battle-Diademed Men of the Island of Britain: And one was diademed above the Three of them:
that was Bedwyr ap Bedrawc.
Bedwyr may be a later interpolation; however, he is often paired with Cai, and the two of them with Gwalchmai ap Gwyar.

Drystan is Tristan, and Hueil is Hoel of Brittany.