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During gladiatorial games in the arena, a vast network of man-powered machinery made animals and scenery appear from beneath a wooden floor as if by magic. (Dave Yoder)

Secrets of the Colosseum

A German archaeologist has finally deciphered the Roman amphitheater's amazing underground labyrinth

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(Continued from page 1)

In the late 16th century, Pope Sixtus V, the builder of Renaissance Rome, tried to transform the Colosseum into a wool factory, with workshops on the arena floor and living quarters in the upper stories. But owing to the tremendous cost, the project was abandoned after he died in 1590.

In the years that followed, the Colosseum became a popular destination for botanists due to the variety of plant life that had taken root among the ruins. As early as 1643, naturalists began compiling detailed catalogs of the flora, listing 337 different species.

By the early 19th century, the hypogeum’s floor lay buried under some 40 feet of earth, and all memory of its function—or even its existence—had been obliterated. In 1813 and 1874, archaeological excavations attempting to reach it were stymied by flooding groundwater. Finally, under Benito Mussolini’s glorification of Classical Rome in the 1930s, workers cleared the hypogeum of earth for good.

Beste and his colleagues spent four years using measuring tapes, plumb lines, spirit levels and generous quantities of paper and pencils to produce technical drawings of the entire hypogeum. “Today we’d probably use a laser scanner for this work, but if we did, we’d miss the fuller understanding that old-fashioned draftsmanship with pencil and paper gives you,” Beste says. “When you do this slow, stubborn drawing, you’re so focused that what you see goes deep into the brain. Gradually, as you work, the image of how things were takes shape in your subconscious.”

Unraveling the site’s tangled history, Beste identified four major building phases and numerous modifications over nearly 400 years of continuous use. Colosseum architects made some changes to allow new methods of stagecraft. Other changes were accidental; a fire sparked by lightning in A.D. 217 gutted the stadium and sent huge blocks of travertine plunging into the hypogeum. Beste also began to decipher the odd marks and incisions in the masonry, having had a solid grounding in Roman mechanical engineering from excavations in southern Italy, where he learned about catapults and other Roman war machines. He also studied the cranes that the Romans used to move large objects, such as 18-foot-tall marble blocks.

By applying his knowledge to eyewitness accounts of the Colosseum’s games, Beste was able to engage in some deductive reverse engineering. Paired vertical channels that he found in certain walls, for example, seemed likely to be tracks for guiding cages or other compartments between the hypogeum and the arena. He’d been working at the site for about a year before he realized that the distinctive semicircular slices in the walls near the vertical channels were likely made to leave space for the revolving bars of large capstans that powered the lifting and lowering of cages and platforms. Then other archaeological elements fell into place, such as the holes in the floor, some with smooth bronze collars, for the capstan shafts, and the diagonal indentations for ramps. There were also square mortises that had held horizontal beams, which supported both the capstans and the flooring between the upper and lower stories of the hypogeum.

To test his ideas, Beste built three scale models. “We made them with the same materials that children use in kindergarten—toothpicks, cardboard, paste, tracing paper,” he says. “But our measurements were precise, and the models helped us to understand how these lifts actually worked.” Sure enough, all the pieces meshed into a compact, powerful elevator system, capable of quickly delivering wild beasts, scenery and equipment into the arena. At the peak of its operation, he concluded, the hypogeum contained 60 capstans, each two stories tall and turned by four men per level. Forty of these capstans lifted animal cages throughout the arena, while the remaining 20 were used to raise scenery sitting on hinged platforms measuring 12 by 15 feet.

Beste also identified 28 smaller platforms (roughly 3 by 3 feet) around the outer rim of the arena—also used for scenery—that were operated through a system of cables, ramps, hoists and counterweights. He even discovered traces of runoff canals that he believes were used to drain the Colosseum after it was flooded from a nearby aqueduct, in order to stage naumachiae, or mock sea battles. The Romans re-enacted these naval engagements with scaled-down warships maneuvering in water three to five feet deep. To create this artificial lake, Colosseum stagehands first removed the arena floor and its underlying wood supports—vertical posts and horizontal beams that left imprints still visible in the retaining wall around the arena floor. (The soggy spectacles ended in the late first century A.D., when the Romans replaced the wood supports with masonry walls, making flood- ing the arena impossible.)


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