One of the greatest movies in cinema history is Ben-Hur. Made during the period where Sword and Sandal movies were popular, this epic telling of the book by Lew Wallace (Ben-Hur: A Tale of the Christ) showed Hollywood at its finest. The epic movie told a great story and had fans riveted to their seats for 212 minutes (that is over three hours including overture) and had many epic scenes (such as the famous chariot scene) that today are still talked about. It won all the categories of its day in the 1960 Academy Awards. A feat that was not toppled until Titanic and later the Lord of the Rings movies. And it saved MGM from bankruptcy as well.
One of the more riveting aspects is when Judah Ben-Hur is sentenced to be a galley slave on the trumped-up charge by his boyhood Roman friend Messala (played by Stephen Boyd) of trying to kill the new governor. A loose tile had fallen off the roof of his home when he passed by spooking his horse and throwing him off. His family is tossed out their home to boot as well. Before he leaves, Judah tells his old friend Messala that he will return, which stuns Messala since it was not likely. When he reaches his ship, he is taken below and becomes one of the slaves rowing the ship. He loses his name and becomes a number. And like all the galley slaves, chained to prevent escape. It is a hopeless existence where you row constantly on the orders of the commander and many die of exhaustion when pushed to the full limit of rowing at high speeds.
While the ships depicted in the movie more or less look like ships used during the period (but probably sturdier), the aspect of Romans using slaves for rowing warships is inaccurate. Instead, nearly everyone who did this task signed up for it and nor were they chained (they were not slaves). In other words, they signed up and were paid to be the engines of the warship. Since they had no artillery or guns, they used catapults to fling fiery objects (or heavy rocks sometimes) or had archers sending flaming arrows to the enemy ships. The standard tactic was to get close enough to board or ram. The front piece of the ship had a heavily constructed bow plate the was designed to break the hull of the other vessel when rammed. Sea battles were not always that easy though as enemy ships tried to maneuver to avoid that. So, you would end up in extended battles as a result. Having a large number of ships though had the effect of causing some enemies to just flee or surrender. At the famous Battle of Actium in 31 BC, when Antony jumped off his ship and swam for a ship departing with Cleopatra’s, the rest of his ships decided to surrender after that knowing the large Roman fleet outnumbered them. On land, Antony’s troops were likewise discouraged from moving east and marching towards Egypt. They sent a message offering to switch sides to Octavian (later Augustus) which was accepted.
Since Romans didn’t use slaves on their ships, where did this idea come from? It turns out it is a bit of post-historical revisionism. Long after the Roman Empire fell, some nations in the 16th, 17th and even into the 18th centuries used slaves in their ships to man the rowers. While they had sails, having rowers gave you an advantage when winds were calm, and your ship had cargo to deliver (or needed speed in battle). However, as time went on and ships built for speed the need for rowers was gone. Older Spanish galleons were likely the only ones that had them into the 19th century in Europe, but the need for slave rowers and slaves in general decreased dramatically as slavery itself came under considerable dislike. Slavery existed in one form or another during the Roman Empire and prior to it by the other powers (Greece, Egypt, Persia, and others). Where the slaves came from made the difference as to what they did as slaves. Most came from wars of conquest or lands Rome occupied. Unskilled slaves (0r those sentenced to slavery for crimes) worked on farms, mines, and mills according to most sources. More educated slaves might end up working in households or if they had some special skills (like mathematics, medicine or other in demand skills), they might be put into places where they skills would be used. Women slaves might end up in prostitution or in households. Romans did not trust slaves to serve in the military except perhaps in support capacities (delivering food etc).
Many people of course know about Spartacus who led the famous revolt between 73-71 BC. He was not, as the movie of the same name, born into slavery. As a Thracian, her served as soldier for Rome but later deserted. When he was captured, he was made into a slave and then eventually helped lead the group of 70 that escaped the gladiator school in Capua. They formed a larger unit of escaped slaves which alarmed citizens (since they seized weapons and food from Romans) and made the Romans look unable to stop them. But they did in 71 BC and ended the revolt. To make it clear they would not tolerate such a revolt again, they crucified every one of the escaped slaves (Spartacus body was never found but believed to have died in battle). Bounties were put into place to be paid when escaped slaves were captured. Far from contributing to the end of the Roman Empire as the movie Spartacus claims, slavery remained in place until its fall. And there were no other slave revolts after this.