Island Walks: The Western Isles, Skye and the Small Islands Book

There's a note here about how translations shouldn't always be trusted so quickly. Bards who had pages transcribe their work may have had a few changes done to it here and there, so readers should take extra caution as to the interpretation of a text, as the obvious, smart thing to do.
This is the principle text that states Arthur wasn't a real figure, but an archetype, and his wild stories can't be believed. Thus, he becomes a nationalistic figure whose exploits can be enjoyed by the citizenry. This book is also a standard on Druidism, instead of relying on Wikipedia.
There's more to bards than storytelling, as that's just the tool used for their job. It's always been difficult for scholars to pinpoint an Arthur figure in history after some Germans and Romans moved into the isle of Britain, but he needn't have been real for the moral lessons to still hold up today.