Battle of Arfderydd

The Battle of Arfderydd (also known as Arderydd) was fought in medieval Britain in AD 573, according to the Annales Cambriae. The opposing armies are identified in a number of Old Welsh sources but vary between them, perhaps suggesting several allied armies were involved. The main adversaries appear to have been Gwenddoleu ap Ceidio and either the princely brothers Peredur and Gwrgi or King Rhydderch Hael of Strathclyde. Gwenddoleu was defeated and killed in the battle. His bard, Myrddin Wyllt, reportedly went mad and ran into the forest. He is one of several proposed origins for the Arthurian character Merlin. The Welsh Triads refer to this battle as one of the "Three Futile Battles of the Island of Britain", along with the Battle of Camlann and the Battle of the Trees.

The 14th-century chronicler John of Fordun's Chronica Gentis Scotorum places the battle on the plain between Liddel and Carwannok. This was identified by W. F. Skene as being at Arthuret, near Longtown, Cumberland (now Cumbria), in North West England.