While a very well-crafted, creative, and funny documentary, it unfortunately falls short in the fact department, glosses over long periods of history, and falls yet again in the "Christian Bad--Everyone Else Good" camp.
I found most interesting the use of "never before published" accounts written by Muslims at the time of the Crusades. What a treasure trove, if they are legitimate. Additionally, building and testing siege engines and actual armor long before Discovery and TLC made such things commonplace was a masterstroke.
I found least interesting the very end of the show, detailing the sack of Constantinople by showing a topless woman (the prostitute on the throne) singing Louisiana blues in Venice.
