It is among those poems in the manuscript thought by Ifor Williams possibly to have originated as part of a sixth-century corpus of Canu Taliesin, a series of poems really composed by the semi-legendary sixth-century court poet of Rheged, Taliesin.
[1] This poem and another of the Taliesin corpus, Argoed Llwyfain, characterise Urien as lord of Yrechwydd/Erechwydd, a place whose whereabouts has occasioned much debate, with implications for guessing the historical extent of the kingdom of Rheged.
The most recent extensive studies, by Andrew Breeze, conclude that Sir Ifor Williams thought it might be the Lake District, with plenty of fresh water (if not too much), where he is hesitantly followed by John Koch.
We can be sure that Yrechwydd was the area bordering that marsh, and hence equivalent to modern North Yorkshire, including York itself.
Reget diffreidyat clot ior agor gwlat vy mod yssyd arnat.
Tan yn tei kyn dyd rac vd yr echwyd.
Ac yny vallwyf hen Ym dygyn agheu aghen.
Lloegr-men know him As they will report: Death's what they get And pain a-plenty, Their dwellings ablaze And their garments seized, And heavy losses And grievous hardship, Getting no deliverance From Urien of Rheged.
Rheged's defender, Renowned lord, land's anchor, I delight in you From all that's reported: Savage your spear-thrust When battle is sounded.
When you charge into battle You wreak a slaughter, Houses fired before daybreak By Yrechwydd'slord.