A cornucopia of history sites that I got from the excellent NCSS History group. If I was a really diligent group member I would save them each individually. But I'm not.
Another of the excellent sourcebooks run by those Jesuits at Fordham Uni. This is the best online primary source research for the ancient world I've found.
Compares Frankish Kingdom with Abbasid Caliphate, Tang China, and the Byzantine Empire. Show's the Franks as the least developed state. Excellent opening anecdote about the failure of a Frankish canal.