The Venedotian Code of the Welsh laws compiled by Iorwerth ap Madog in the early 13th century[6] contains a list of the privileges of the men of Arfon.
In his comprehensive discussion of the works by and attributed to Taliesin, John Morris-Jones notes that the particulars of the marwnad are everywhere consistent with the historical record and nowhere inconsistent, and likely a product of the 6th century, a view shared by notable skeptics such as Thomas Stephens.
[7] The Venedotian Code says that the northern prince Elidyr Mwynfawr ap Gorwst Priodawr (English: Elidyr the Courteous, son of Gorwst Priodawr) had been slain at Aber Mewydus (now called "Cadnant", or "Battle Brook") in Arfon, not far from Rhun's llys (English: royal court) at Llanbeblig.
It is supposed to have been one of Rhun's strongholds, and while definitive evidence of this is lacking, it is circumstantially supported by archeological research and the antiquity of the name Caerhun.
[12][13] Furthermore, it guards an important crossing of the River Conwy at Tal-y-Cafn which leads to the pass at Bwlch-y-Ddeufaen,[14] an entrance to Eryri (Snowdonia), the defensive heartland of the Kingdom of Gwynedd.
[18] The story tells of events where Taliesin is placed in difficult or impossible situations but invariably overcomes all obstacles, usually through feats of magic.
In one passage, Maelgwn Gwynedd sends his son Rhun on a mission to seduce the wife of Elffin ap Gwyddno.
[22] There is no confirming evidence that such a person existed, and it is contradicted by records such as the royal genealogies, which have Rhun as the father (not the son) of Beli.