A historian says the naval battle in 'Gladiator II' only got one thing wrong

• "Gladiator II" features a naval battle that occurs at the Colosseum for the crowd's amusement.
• The scene is rooted in real-life naval battles that began during Julius Caesar's reign in Rome.
• But it's unlikely that the staged fights included sharks in the water.

Ridley Scott's "Gladiator II" takes a few creative liberties and diverges from history to up the ante for audiences.

"Gladiator II" is set 15 years after Russell Crowe's Maximus Decimus Meridius died in the Colosseum in the 2000 movie "Gladiator." Now under the rule of the unhinged twin emperors Geta (Joseph Quinn) and Caracalla (Fred Hechinger), cruel entertainment has reached new levels in the arena.

Lucius (Paul Mescal), the son of Maximus and Lucilla (Connie Nielsen), is one of the men who's forced to fight to the death in the Colosseum for the amusement of the emperors and the similarly bloodthirsty crowds.

In one scene, the Colosseum floor is flooded with water in honor of Poseidon, the god of the sea. To add to the danger, tiger sharks swim in the water, ready to feast on the humans.

Naval warfare ensues as two boats enter the arena to fight each other, the Romans versus Lucius and the other gladiators.

The boats circle the Colosseum before crashing into each other. Then, the men begin fighting viciously. As some of them fall off the boats and to their deaths, the sharks in the water swiftly tear them apart.

As far-fetched as the battle might seem, the scene was, at least partially, inspired by history.

Staged naval battles really did happen in Rome

Water spectacles in Rome go back to the first century BC. Areas, including the Colosseum, were flooded with water for staged fights. These mock naval battles, known as naumachia, began during Julius Caesar's rule in Rome.

According to National Geographic, in 80 AD, two naumachiae took place, one in an artificial lake and another in the Colosseum.

It's unclear if water entered the Colosseum via aqueducts or the arena's sluice gates and chambers that were used to drain and fill the space.

"It was quite amazing," Neil Corbould, special effects supervisor Neil Corbould of Industrial Light and Magic, said in the production notes for the film. "The boats they used in these battles were built only for that purpose. They were flat-bottomed because the water was so shallow."

Alison Futrell, an associate professor of Roman history at the University of Arizona, told Business Insider that the Colosseum's enclosed, limited size meant that actual boats were probably "cumbersome to maneuver" around the arena.

However, staged naval battles at the Colosseum could work if the boats were sized down.

"Maybe smaller sort of quasi-miniaturized boats that give the flavor of warships and that maybe accommodate greater visibility for the specifics of the combat too," Futrell said. "Because there are fans who want to really see what kind of fighting is going on there."

The battles probably didn't include sharks

History shows that people in Rome were at least aware that sea creatures existed.

"There are encyclopedists from antiquity who talk about sea creatures, and they're aware of shark-like things," Futrell said.

However, Futrell said that these shark-like creatures appear to have been located in the Indian Ocean rather than the Mediterranean. Plus, most of the sea animals referenced were mammals, not fish like sharks.

Futrell said that the Romans were aware of dolphins and orcas, which are both mammals. That said, there isn't a lot of evidence that the Romans were regularly building tanks big enough to allow people to interact with the creatures up close.

"But they knew about them as a draw and did make some effort at certain points in time to make them a kind of show in some ways," Futrell said.

There's evidence that in one such instance, under Emperor Claudius' rule, an orca traveled to the Tiber River and some effort was made to turn the event into a spectacle by blocking off access points so people could see the creature.

The sharks featured in "Gladiator II" are most likely an addition from Scott, who tends to include animals in his movies. There doesn't seem to be any historical evidence of sharks being part of these naval battles, though.

"Probably not sharks, specifically, and only rarely orca," Futrell said. "They're challenging to work with."

"Gladiator II" is now playing in theaters.