I completely agree. Medieval: Total War was a constant challenge. For one thing, you actually had to worry about assassins, not to mention all the events such as drought, famines, peasant crusades... And the civil war feature was pretty good. It did not need mods to be challenging.

The music was more interesting than the current ones, too.

But to Medieval 2: Total War's credit, you had a nifty video for assassinating the pope.