Battle of Arfderydd

The Battle of Arfderydd was fought in 573 in the borderlands of what is now northern England and southern Scotland. The Annales Cambriae records the battle, while later Welsh tradition associates the victory with Peredur and Gwrgi and the defeat with the death of Gwenddoleu ap Ceidio.

Later poetry and legend made Arfderydd central to the story of Myrddin Wyllt, who is said to have fought on the losing side, become traumatised or maddened by the slaughter and retreat into the Caledonian Forest. These traditions became one strand in the later development of Merlin.

It should be used instead of its broader Early Medieval Rheged and Northumbria parent when Arfderydd itself directly shapes the plot.