If locations of other conflicts discussed in this book have been unclear, that of Arfderydd has long been known. In 1868 the Scottish antiquary W. F. Skene (1809– 1892) identified it as Arthuret in north- east Cumbria. We can be sure that this battle took place near Carlisle in 573 (or perhaps 575). Nevertheless, more can be said on its location and the meaning of its name. What follows thus has two functions: it reviews what has been written on the conflict between 1860 and 2019, and then sets out a new etymology for Arfderydd, with implications for where the action took place.

Annales Cambriae records the encounter under the year 573. The best manuscript here is London, British Library, MS Harley 3859 (copied in about 1100), which has merely Bellum Armterid. But London, National Archives, MS E.164/ 1 (of the thirteenth century) adds to this, saying the encounter was ‘between the sons of Eliffer, and Gwenddolau son of Ceidio, in which battle Gwenddolau fell. Merlin went mad.’ The mention of Merlin (Merlinus, a form deriving from Geoffrey of Monmouth) shows how a historical event has gained the trappings of legend.

A step forward was made by W. F. Skene in his Four Ancient Books of Wales (Edinburgh, 1868) and elsewhere, where he identified Arfderydd as Arthuret, south of the Esk in what is now Cumbria. Sir John Rhys (1840– 1915), fertile in ideas now discredited, describing Carlisle as ‘the most important town of the Northern Cumbrians’, considered ‘much of its importance’ lost thanks to the battle, its site identified by some with Arthuret (‘and by others with Airdrie’, east of Glasgow). The victor was Rhydderch, who ‘thereupon fixed his headquarters on a rock in the Clyde’, the massive volcanic height of Dumbarton ‘fort of Britons’. If only we could be so sure of events. There seems no archaeological evidence for Carlisle as a major centre of population in the sixth century, and it is effectively unknown in early Welsh tradition, unlike the realm of Rheged, with its capital in east Cumbria, at or near Penrith.

Sir John Lloyd, a great historian, agreed with Skene on the site, regarding the encounter as ‘a triumph won by Rhydderch [of Strathclyde] over Gwenddoleu ap Ceidio.’ Yet he rejected the notion (which Skene thought implied by later hagiography) of its also being a victory of Christianity over semi- paganism.