How Historically Accurate Is The Film Gladiator?

The central character of Maximus is an invention and nothing like a deposed general becoming a gladiator and undermining the rule of an emperor occurred. Marcus Aurelius and his son Commodus are true historical characters, however, though the film's central conceit, that Marcus Aurelius wished to set aside tradition and see someone other than Commodus succeed him, is not only false but the very opposite of the truth. Direct inheritance of the imperial throne had not been the norm in Rome for generations yet Marcus Aurelius went out of his way to see that his biological son would succeed him.  There is no evidence that Commodus actually killed his father though he did become emperor on his father's death and ruled for 12 years.

Interestingly, what might seem like the most superficially implausible aspect of the film's plot ~ emperor Commodus actually fighting as a gladiator in the arena ~ did, in fact, occur, not only once but many times. The contests are believed to have been rigged, with the opponents having been drugged in advance.