Local tradition places Vortigern in Nant Gwrtheyrn (the ‘Valley of Vortigern’), a rocky valley leading down from Yr Eifl to the west coast of the Lleyn peninsula. Vortigern was supposed to have once had his headquarters there.
Here we also find his ‘city’: Castel Gwrtheyrn, once so marked on Ordnance Survey maps, but now unlocated. The best candidate for this fortress surely is Tre’r Ceiri, which lies just on the other slope of Yr Eifl, very close to the valley. His grave, Bedd Gwrtheyrn, is also to be found somewhere around here, as there are several locations bearing names familiar to us, such as Carn Fadrun, or the ‘fort of Modrun’ (she was a granddaughter of Vortigern) further south.
The source for this name of this valley, which is the only one in Wales named after Vortigern, is not known. Vortigern’s legends do take him to north Wales (especially Snowdonia), but never to the Lleyn peninsula itself. But maybe the legend about his death did travel to this area, as there are many more places that are connected with Vortigern in the direct neighborhood.
At least until around the year 1700 a stone grave covered with a turf mound existed there, which was called Vortigern’s Grave (Bedd Gwrtheyrn) by the local population. George Borrow, writing in 1862 (Wild Wales), described it as follows: “It was in a wind-beaten valley of Snowdon, near the sea, that his dead body decked in green armour had a mound of earth and stones raised over it”.
Badbury Rings is supposed to be a candidate for the Battle of Badon Hill, where Arthur decisively beat the Anglo-Saxons. However, it is no hill at all, just the remains of a settlement with earth walls and ditches around it. It was called Durnovaria during Roman times, and 4 Roman roads meet here. The views are very beautifull, I can recommend a visit to anyone .