A passing reference in the elegy Gwarchan Cynfelyn[2] (7th century), preserved in the Book of Aneirin, reckoned to be its earliest mention in literature.

The earliest reference to Trwyth in the Arthurian context[9] occurs in the tract De Mirabilibus Britanniae (or Mirabilia in shorthand), variously titled in English as "Wonders of Britain".

anoetheu[24]) by Ysbaddaden, the giant whose daughter Olwen Culhwch seeks, of obtaining the comb and scissors from Twrch's head.

Further, Ysbaddaden states that the only hound who can hunt Twrch is Drudwyn, the whelp of Greid, and then goes on to list the requirements of the leash, collar, and chain needed to hold the dog, and Mabon ap Modron who must be recruited as the sole person capable of handling this dog Drudwyn for the hunt.

[32] Although the sword (cledyf) of Wrnach the giant is prescribed as the sole weapon capable of killing the boar,[33][34][b] it is used by Arthur's men to commit murder of the giant, but does not get used upon the boar[c][35] Ultimately Ysbaddaden calls on Culhwch to seek out Arthur, Culhwch's cousin, to help him hunt Twrch.

[d] The men ultimately failed this, though they did manage to wrest the razor, scissors, and later the comb from the boar while it waded in the Severn's water.

[43] However, Rachel Bromwich took a position contrary to Rhys, and was skeptical that there should be any reason to conclude there had to be any mutual borrowing between the Irish and the Welsh regarding the boar names.

The Knight of the Round Table named "Tor son of Ares" who appears in Chrétien de Troyes's romance Erec et Enide may have been reinvented out of "Twrch son of Tared" in Culhwch ac Olwen, an idea advanced by Idris Llewelyn Foster[47] Some scholars venture that the authentic patronym in the original lore gave the father's name as closer to "Ares".