I'm glad someone out there can follow through on a great idea for a hoax, viz. a fifth branch of the Mabinogion. Also includes the splendid vocabulary word teichoscopia,

teichoscopia, a topos of heroic narratives throughout the Indo-European world, in which the heroes of an opposing army are pointed out one by one from the walls or ramparts of a besieged city. Examples occur in the Irish Táin Bó Cúailnge, the Iliad, and the Ramayana