Excerpted from Fox Tossing: And Other Forgotten and Dangerous Sports, Pastimes, and Games by Edward Brooke-Hitching. Out now from Touchstone.

In 46 B.C., on the orders of Julius Caesar, an enormous basin was dug in the Campus Martius (Field of Mars) outside the walls of Rome and filled with water. For this event (to celebrate the emperor’s recent Gallic, Alexandrian, Pontic, and African triumphs), two fleets of biremes, triremes, and quadremes, representing Tyre and Egypt, clashed in a battle of epic scale involving more than 6,000 prisoners who played the parts of soldiers and rowers. Also on record is the staged aquatic battle organized in 40 B.C. by Sextus Pompey for the entertainment of his troops that featured prisoners of war fighting to the death to celebrate his victory over Salvidienus Rufus and the occupation of Sicily.

These naumachiae were giant sea battles re-enacted in flooded Roman arenas. Condemned criminals and captured prisoners of war fought to the death as they played out famous naval campaigns for the entertainment of a crowd. The events required sophisticated planning and execution, and as such were only performed with the approval of the emperor to mark special occasions.

Naumachiae are thought to date back to the third century B.C., when the Roman Gen. Scipio Africanus staged the re-enactments using his own troops, as mentioned by Suetonius in his Lives of the Twelve Caesars, and by Cassius Dio in his Roman History. Together with his favored general, Marcus Agrippa, Emperor Augustus developed large areas of the Campus Martius for the sport, which included the Baths of Agrippa and also the Stagnum Agrippae (Lake of Agrippa), an ornamental body of water considerably larger than that dug by Julius Caesar, possessing dimensions of 1,800 by 1,200 (Roman) feet and located beside the River Tiber, with water piped in via a newly completed aqueduct. One of the grandest naumachiae ever mounted, though, was that of Claudius in A.D. 52. To mark the opening of a canal that was to later dry the Fucine Lake, a naval battle between Rhodes and Sicily was staged, consisting of 19,000 soldiers manning 100 ships.

Little is known about the specifics of how the sea battles were conducted. Aquatic displays as a whole were popular at the time and included exhibitions of captured marine curiosities, water ballets, and pantomimes, so it is possible that the events were entirely theatrical. It is thought that two opposing fleets would face off, but as it is unclear how much of the action was pre-orchestrated, the events are categorized somewhere between sport and theatrical recreation. How fierce the battles were is also a mystery, although the fact that participants were usually facing imminent execution either way must have meant there was little motivation to participate enthusiastically. Indeed, Tacitus writes about Claudius being forced to dispatch the imperial guard on rafts during a naumachia in A.D. 52 to impel the two sides into fighting.

In terms of venue, as well as the aforementioned basins, natural settings such as lakes and the Rhegium coast were used, but there is also evidence to suggest that the battles were hosted in amphitheaters. For years archaeologists have debated whether the dual-level labyrinth of chambers beneath the Colosseum arena known as the hypogea support or disprove the notion that aquatic displays were staged in the arena. The existing walls of the hypogea were first thought to disprove the idea, as they would obstruct such a thing from happening, but it has since been shown that the walls were added much later, possibly as late as the Middle Ages, and therefore the early form of the amphitheater would have been capable of holding the events. This is further supported by the discovery that the drains were built as part of the original foundation.

While excavations have still failed to turn up specific evidence of the naumachiae being staged in the Colosseum, such as remnants of ships or weapons used, ancient sources indicate that naumachiae did indeed take place. It is thought that for this to have been successful the ships involved must have been smaller in scale. The Colosseum is thought to have housed these spectacles on its launch. The construction was initiated by Vespasian around A.D. 73 on the site of an artificial lake built by Nero, and, for its two inauguration ceremonies, aquatic displays were performed each time, according to Martial, who writes in his Liber Spectaculorum about witnessing fleets, land animals in a naval environment, and carts running upon the water. Despite living much later than the events he describes, and therefore being a slightly less reliable source, Cassius Dio (ca. 164–235) wrote about the inauguration of Titus and describes a naumachia in the amphitheater:

For [Titus] suddenly filled this same theater with water and brought in horses and bulls and some other domesticated animals that have been taught to behave in the liquid element just as on land. He also brought in people on ships, who engaged in a sea-fight there, impersonating the Corcyreans and Corinthians; and others gave a similar exhibition outside the city in the grove of Gaius and Lucius, a place Augustus had once excavated for this very purpose.

The naumachiae were clearly used more as demonstrations of imperial might than anything else, designed to inspire awe with the sheer scale of the spectacle. Literary evidence suggests that naumachiae only took place in Rome and declined in popularity after the first century, the last one being recorded in 89.

Excerpted from Fox Tossing: And Other Forgotten and Dangerous Sports, Pastimes, and Games by Edward Brooke-Hitching. Copyright © 2015 by Edward Brooke-Hitching. Reprinted with permission from Touchstone, a Division of Simon & Schuster, Inc.