Archaeologists have long believed that the forerunners of the cranes that now dot the skylines of cities across the globe were invented by Greek engineers around 515 B.C. But a new study suggests that earlier versions of the lifting machines were being used on the Greek peninsula 150 years earlier.
The evidence comes from temples at the ancient cities of Isthmia and Corinth dating from 700 to 650 B.C. The 440- to 880-pound blocks used to construct the temples have unusual twin grooves running along the bottoms of the stones. Researchers have argued about the purpose of the grooves for decades. That's why architecture professor Alessandro Pierattini of the University of Notre Dame decided to take a closer look.
“Scholars have proposed two alternative interpretations for these grooves: they served either for attaching the blocks to lifting machines or for moving blocks in the quarry,” he tells George Dvorsky at Gizmodo. “My reexamination concludes that the grooves served for lifting and testify to the first experiments with lifting architectural blocks in Greek history.”
The study appears in the Annual of the British School at Athens.
What those early lifting machine may have looked like and how they operated is up for debate. The Corinthians, Pierattini argues, were known as master shipbuilders, and that temple engineers could have used the frameworks they used to construct boats and lower sarcophagi into crypts to hoist up the building stones. Those frames are not technically cranes, since they didn’t use winches to pull up the stone blocks.
Using ropes and replica stones, Pierattini experimented with placing some stones himself. What he found is that the grooves not only allow for lifting, but also help wedge the blocks into place. “With heavy stone blocks and high friction between stone surfaces, this was a highly problematic step of construction that in later times would require sets of purpose-made holes for using metal levers,” he tells Dvorsky.
The grooves could have allowed the builders to lower the stones onto the walls, roll them into place using rollers, lever them up to remove the rollers, then extract the ropes from under the blocks without lifting them back up.
Prior to the use of these machines, it was believed the Greeks, like many other cultures including the Egyptians, used ramps made of dirt or mudbricks to put stones into place. The first archaeological indication that a true crane was being used dates to temples from 515 B.C. that show distinctive marks where lifting tongs were used to put stones into place.
So why did the crane develop in Greece, when many other cultures were also building incredibly complex monuments and temples? Unlike kingdoms like Egypt or Assyria, which had large masses of unskilled labor that could be used to break their backs constructing ramps, the Greeks relied on small teams of professional builders for their projects. That specialization led to innovations in design and more efficient machines like the use of cranes.
In a press release, Pierattini says it’s hard to overestimate the importance of that one single invention. “The foremost discovery of the Greeks in building technology is the crane,” he says. “No previous civilizations are known to have used it, and it has remained central to building construction without remarkable changes for nearly 25 centuries — because it was perfect.”