I'm currently reading Henry of Huntingdon's "History of the English People." I'm currently getting through the chapter of all the stuff leading up to 1066 - Aethelred's floundering, Swein's death, Cnut's ascendency, and then Aethelred's death. Then Aethelred's son Edmund comes into the picture.
It's one of these eye-popping little early history stories, although upon reflection, it's really the villain, Eadric, who makes it. Underdog victories, attempts at treachery, underdog keeps going anyway, a duel between kings, a peace accord, a final treachery most foul, and the villain's poetic come-uppance.
I've only just started poking into this - Henry's account isn't the only one, and some of the devices he uses (e.g. the duel, death-by-privy-assassin) are just soooo literary that I suspect he's playing with facts for a good story. BUT IT'S A GOOD STORY. I'm not surprised to learn that there's a minor Elizabethan play about him - and that's got it's own good story to it, since some guys are insisting that it's a lost early Shakespeare!
Definitely thinking I want to do something with this guy. Not sure what yet.