In listening to the History of Rome podcast, I was somewhat saddened, though hardly shocked, to learn that "Gladiator" (2000) wasn't really very faithful to history. Well, it was accurate in the sense that there was once a pretty good emperor named Marcus Aurelius who was succeeded by his son, a pretty crappy emperor named Commodus, and Commodus' sister later hatched a plot to assassinate him, but it failed. And there was a Roman general named Maximilianus who scored some big wins late in the Germanic wars. Otherwise, the whole plot of "Gladiator" was just kind of made up.
Still, pretty good plot. And on the more general details, I'd say "Gladiator" was more historically accurate than, say, "Dirty Dancing."