And also, for one of the most obviously entirely mythical aspects of the legends, it has possibly the most supporting evidence -- Dinas Emrys is one of the very few locations which is known to be a real place. At Dinas Emrys there is a rocky hillock with a castle atop it, and in the middle of that castle there is a pool (specifically the legend was that the vermes were fighting in a pool of course), and above the pool there is an unusual platform. Considering that nearly every other location in the Arthurian legend has not been tied to anywhere specific in modern times, much less have any other corroborating evidence, this is really quite strange.