I'm currently playing the crusades campaign as Jerusalem and have been fighting the Byzantines. I commanded my cavalry to charge a unit of Varangian Guard, and it destroyed my cavalry! I'm aware that that can happen when you charge spearmen or pikemen, but is there a list anywhere of all the units you should avoid charging? Later I had the same thing happen when I charged some Muslim javelinmen.

The Varangian Guard really didn't make any sense, because they just have axes. I thought I would use a couple of simultaneous cavalry charges to take the unit out so my infantry wouldn't have to get into it with them, but it didn't work at all.