King Arthur: A Man for the Ages
Looks at both the historical and the legendary elements of the story of King Arthur.

King Arthur and the Matter of Britain
LARGE list of links and information on Arthur and his role in the development of Britain after the exodus of Roman troops.

The Camelot Project
Impressive collection of texts and images relating to the Matter of Britain.

Llys Arthur
Focus is on the Welsh part of the story, including the idea that Arthur himself was Welsh.

Encyclopedia entry
Heavy on the detail and links, this entry in Wikipedia, the free online encyclopedia, is top-notch.

King Arthur at Britannia
Impressive display of knowledge and images concerning the story of Arthur and the development of Britain.

Ancient British History
Site focuses on the British Isles, from the early days to the Norman Conquest, including quite a few articles on Arthur.

The Historicity and Historicization of Arthur
Long but well-thought-out article examining the historical claims on Arthur as King.

Dark Age Britain
See what life was like after the Romans left.

Dark Age Scotland
After the Romans left, the Scots, Picts, and Caledonians fought for control of Scotland.