Really solid little intro to the early Middle Ages. Covers the breakup of Rome and Germanic tribes, Charlemagne and the Vikings and early feudalism and ends with the First Crusade.
I never knew that the Normans were originally Vikings (Rollo!) who were given a duchy (Hello Normandy) by the Franks. I can certainly see where Tolkien got some of his names from. I'm pretty sure there is a Rollo Bolger in the Fellowship of the Ring. It's a very Hobbity name.