The Colosseum in Rome is one of the most iconic surviving monuments of the Roman Empire. This massive amphitheater could hold over 50,000 spectators who gathered to watch gladiatorial combats, wild beast hunts, public executions, and mock naval battles. But how did the ancient Romans light up such a massive structure without electricity? The ingenious techniques used by Roman electricians to illuminate the Colosseum at night may surprise you.

Lighting Fixtures in the Colosseum

The Colosseum had an elaborate system of lighting fixtures to allow events to proceed well after sunset. Sources describe bronze and silver lamp holders fitted into the archways of the upper tiers to provide light. There were likely thousands of these lamp holders throughout the structure. In the arena itself, there were also raised lighting posts to ensure the spectators had a clear view of the action from above.

Oil Lamps Provided the Light

The lamp holders in the Colosseum were fitted with oil lamps which burned olive oil. These open, shallow dishes held a fiber wick which was lit to produce the flame. Olive oil was commonly used for illumination in Roman times as it burns cleanly and efficiently. The lighting posts around the arena floor likely held larger elevated oil lamps for maximum visibility.

Reflectors Increased the Light

Behind each lamp was a curved bronze mirror that amplified and directed the light outwards toward the audience. These ancient reflectors made the best use of the oil lamps' flames to illuminate the vast interior spaces. The addition of mirrors demonstrates the Romans' advanced grasp of optics and light.

Unexpected Materials Used in Roman Candles

While oil lamps provided steady ambient light, Roman candles were also used for brilliant displays in the Colosseum. But these pyrotechnics were fueled by some peculiar and unexpected ingredients.

Pine Resin For Dazzling Sparks

The Roman candles contained a mixture of pine resin, lime, and charcoal. When ignited, the pine resin produced eye-catching spurts of sparks and flames. Pine resin was highly flammable and burned rapidly at high temperature. This made it perfect for ancient pyrotechnics.

Producing Vibrant Purple Sparks

To create colored sparks, the Romans added unusual compounds to the candles. Salt, for example, produced a bright yellow color. But even more striking were the vibrant purple sparks generated by adding scales of copper to the mixture. When burned, the copper salts emitted a brilliant purple glow over the Colosseum crowds.

Adding Calcium for Deep Red Hues

The Romans also used innovative chemistry to create deep red colors for their pyrotechnics. Calcium oxide, also known as quicklime, was added to the candles to produce a rich, deep crimson glow through a flame test reaction. When burned, the calcium emitted wavelengths associated with a red hue which dazzled spectators.

Making Pyrotechnic Displays a Dramatic Show

The Roman candles added drama and spectacle to the events held in the Colosseum. The dazzling colors and loud reports would have elicited cheers and applause from the crowds.

Launching Candles from Clay Pots

The candles were launched by lighting the fuse of a taper inserted into a clay pot containing the pyrotechnic mixture. This allowed them to be propelled high up into the air over the arena. The height added to the impressiveness of the display.

Synchronizing with Music and Action

The candle launches were carefully timed to sync with music, action, or outcomes during the event. As soon as an animal was hunted or a gladiator defeated, a round of fireballs or colored sparks would be set off to amplify the excitement. This synchronization required great skill.

Signaling to Communicate with Crowds

The Romans also used candles and fireworks as a signaling system to the crowds. Certain colors, patterns, or sequences communicated what was about to happen next, who had won a match, or when events were finished for the day. This became an important part of the experience in the Colosseum stands.

Legacy of Roman Ingenuity

The novel ways that ancient Roman electricians managed to light up the Colosseum are remarkable when we consider it was achieved without electricity. Their clever use of oil lamps, reflectors, pyrotechnics, and color-generating compounds demonstrate the innovation and chemical mastery of the civilization. It's just one example of how ahead of their time the Romans were in engineering and technology.

The next time I walk amongst the ruins of the Colosseum, I'll think about the team of electricians who made it possible for Romans to gather and enjoy incredible spectacles of entertainment and sporting competition long after sunset. Their legacy is still awe-inspiring today.