How historically accurate is the Gladiator?

This article contains spoilers.

The Gladiator was a film released in 2000 starring Russell Crowe that focused on General Maximus Decimus Meridius, who was enslaved after escaping his execution for not supporting the new Roman emperor Commodus (staring Joaquin Phoenix). Maximus rises as a well skilled gladiator, eventually making it to Rome where he participates in the gladiator games sponsored by Commodus. After Commodus learns of Maximus, both characters want to kill the other. Maximus attempts to conspire with those in the Senate who dislike Commodus, while Commodus attempts to have Maximus killed in the gladiator battles.

Battles in Germania

The movie begins with the ailing Marcus Aurelius, the emperor of Rome, watching Maximus leading a battle against a Germany tribe, where the battle is portrayed as crucial in bringing peace to Roman Empire's northern frontier. During the reign of Aurelius, there were prolonged wars in Germania. Wars there were largely inconclusive, although they were close to annexing Moravia and West Slovakia during his reign. The movie depicts the emperor being killed by his son Commodus, although in reality Commodus was already co-emperor. In fact, there is no evidence that Commodus had any difficult relationship with his father. Furthermore, although Maximus is mostly a fictional character, it is not likely Marcus Aurelius would appoint a general as protector of the empire, as suggested in the movie where shortly before his death the fictional Marcus Aurelius asked Maximus to lead the empire. In fact, a conflict in Marcus Aurlieus' mind was whether to return power to the Senate rather than have it mostly be with the emperor. This is unlikely as Marcus Aurlieus, although often considered a wise emperor and even called the "philosopher king," as suggested in the film, he still believed in holding power closely and even passed power to his son, something a Roman Emperor had not done for about a century.

In fact, Marcus Aurlieus appointed his son as successor long before he died in 166 (he died in 180 CE), making it clear that Comodus was his choice all along. His appoint of his son was controversial, as shown in the film, as Commodus was considered erratic and likely had mental problems, as indicated in the film