4th century Saxons on Hadrians Wall?

[Flavivs Aetivs]

Sounds like a great book for me. ;-)

And me as well, I always viewed the collapse of britain as the result of granting land to mercenaries and the degredation of the Roman-Style government resulting in the collapse of control to essentially small city-states, with some retained authority in Londinium and a portion of Britain until c. 450.