Here’s the situation: You spot Roman attack ships headed for your shores. Do you order your troops to ready the cannons? Or–in an ancient MacGyver move–do you use a parabolic mirror, focusing the sun’s rays to set the ships on fire? Though the latter is clearly more suave, recent research has shown that the 212 B.C. legend about Archimedes’ mirror defense is unlikely: He probably pulled out the big guns instead.

Cesar Rossi, a mechanical engineer at the University of Naples in Italy, figured out the numbers. A steam cannon–like the ones Leonardo da Vinci drew in the 1400s–could use less than a tenth of a cup of water to fire a hollow clay ball, at 134 miles per hour, to hit a target 492 feet away. For comparison, an 1854 American Civil War Howitzer cannon could fire a ball about ten times farther–a little less than a mile.

Rossi presented this research at the International World Conference in Syracuse, Italy (the site of the historic Roman attack on the Greek colony) earlier this month. He told LiveScience that after looking at both the historical references to the battle and the feasibility of using the mirrors on moving ships, that the cannons were “much more reasonable than the use of burning mirrors.” The hollow clay cannon balls could have been filled with a mix of incendiary chemicals that would have set the ships afire on impact, Rossi suggests.

In 2005, MIT students recreated the mirror defense and managed to set a wooden “ship” ablaze. On the roof of a Cambridge parking garage, they scorched the ship, but their test required ideal weather conditions and a stationary target. Rossi hopes to team up with other researchers to create his own reenactment using the steam cannons.

Cannons or mirrors, Archimedes couldn’t save Syracuse–and the Romans’ success meant Archimedes’ end.

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Image: Wikimedia / Giulio Parigi, 1600