It has to be said that the Shieldwall supplement, whilst full of information on the various nations of the period is quite heroic in it's vision. Nothing wrong with this of course, in fact many will be happy to see an Early Medieval rule set that is so.
Just remember that WAB 1, 1.5 or WAB 2 is needed too- I thought I ought to mention it ,though I expect that you already know this
Darrell.