Before the battle with the Germanic tribes at the beginning of the movie, Quintus' remark that "a people should know when they're conquered," is very ironic to anyone who knows that Rome never ultimately managed to completely conquer Germania.
When he first meets him in the arena (before realizing who he is), Commodus tells Maximus that his nephew "insists you are Hector reborn...or was it Hercules?" The real-life Commodus believed he was the reincarnation of Hercules.
"Didn't the Romans win the Battle of Carthage?" Yes, they did, Comodotus... but as noted under Artistic License in the main page, the "home team" of chariot riding archers (including women) are about as far removed from the three lines of the Pre-Marian Roman Army. If anything, Maximus and his team were what the actual Romans of the era would be (even using a similar shield model painted black). And, by using Roman tactics (formation fighting, aggressively plunging into gaps in the enemy, etc.) they did indeed win the recreation of the Battle of Zama, winning the crowd in the process.
The trees along the path of Maximus' home? They're cypress. In Roman mythology, the cypress tree was linked to Pluto, the god of the underworld. Re-watch the movie with that in mind... doubles as Fridge Horror.
It's an Unbuilt Trope, sure, but after Superman enters the picture in 1938 Danner looks nothing but weak and cowardly in comparison. Clark Kent could use his powers only discreetly like Danner does, but instead he decides that the right thing to do is to devote his existence to helping those in need, regardless of what people thought, or even if the law stood in his way. That's heroic. Here's why the title is brilliant though. Clark Kent is a Superman because he fights for others, but just like the titular warriors of the more famous film, Hugo Danner is a Gladiator: he fights for survival. It just happens not to be physical survival.