2,000 Years Before Modern Technology, the Greeks Had Built the World’s First Computer (So Advanced That It Still Baffles Scientists)

Over 120 years ago, sponge divers off the coast of the Greek island Antikythera unearthed one of the most enigmatic technological artifacts in human history. Hidden among statues, coins, glassware, and jewelry from a Roman-era shipwreck was a corroded cluster of bronze gears.

Initially mistaken for debris, this fragmented object would later be identified as the Antikythera mechanism—a shoebox-sized device that has stunned archaeologists, engineers, and physicists for decades. Now housed at the National Archaeological Museum in Athens, the mechanism is often described as the world’s first analog computer.

It once displayed a model of the cosmos so precise and intricate that some have compared it to modern clockwork. For scientists and historians, the device represents a vivid example of how advanced ancient Greek astronomy and engineering really were.

An Accidental Dive Into Ancient Innovation

The discovery of the Antikythera mechanism in 1900 was completely unintentional. A team of sponge divers, weathering a storm near Antikythera, began exploring the seafloor. One diver, Elias Stadiatis, surfaced in panic, describing a scene filled with “rotting corpses of women and horses”—which turned out to be bronze and marble statues.

Among the first finds was a bronze arm, and eventually, a corroded mechanical object would reveal itself as something far more significant. Recovered from a shipwreck dating back to the first century B.C.E., the device’s true nature wasn’t understood until 1902, when politician Spyridon Stais noticed gear teeth in a fragment.

His cousin, Valerios Stais, the museum’s director, brought it to scholarly attention. German classicist Albert Rehm was the first to recognize its function as an astronomical calculator, identifying epicyclic gears and inscriptions like “Pachon”—the ninth month in the Egyptian calendar—on its surface.

The Cosmos in a Box

The device’s sophistication was unheard of for its time. Crafted with tools such as bow drills and vertical lathes, it featured over 30 gear wheels that could replicate celestial cycles with millimeter precision. Its front dial, operated by a hand crank, tracked the positions of the sun, moon, and the five planets known to the Greeks—Mercury, Venus, Mars, Jupiter, and Saturn.

The rear included two spiral dials: one modeled the Metonic cycle, a 19-year lunar calendar, and the other depicted the Saros cycle, used to predict eclipses. One smaller dial even marked Olympic Games and other Panhellenic festivals.

But perhaps most impressive was the inclusion of a pin-and-slot mechanism that simulated the moon’s variable velocity—something observable only when noting how its speed changes at perigee and apogee. This feature relied on epicyclic gearing, a technique where gears rotate around other gears, mounted on eccentric axles.

From Archimedes to Modern Scans

The origin of the Antikythera mechanism remains debated. Some scholars argue it was inspired by earlier designs of Archimedes, the famed Syracusan mathematician whose astronomical spheres were said to mimic celestial motion. Roman statesman Cicero described such a device brought back by Marcus Marcellus after the conquest of Syracuse in 212 B.C.E.

While the Antikythera mechanism likely dates from between the third and first centuries B.C.E., it may reflect a long lineage of Hellenistic instruments—none of which have survived.The modern era of research began in the 1950s when physicist Derek de Solla Price studied the mechanism stored in cigar boxes.

With help from Greek physicist Charalambos Karakalos, he used X-rays to examine the internal structure. In his 1974 book Gears from the Greeks, Price described the mechanism as “a calculating machine” more than a decorative object. He famously compared its discovery to “opening a pyramid and finding an atomic bomb.”

Price’s work attracted scientists like Tony Freeth, a mathematician and documentary filmmaker who spearheaded a new phase of analysis in the 2000s. With astrophysicist Mike Edmunds, Freeth launched a scanning project using high-resolution X-ray tomography.

In 2005, they transported an eight-ton imaging device, nicknamed the “Blade Runner,” to the museum in Athens. Along with Reflectance Transformation Imaging (RTI) developed with Hewlett-Packard, these scans revealed thousands of hidden characters and gear positions invisible to the naked eye.

The Ongoing Puzzle and Fresh Controversy

Despite breakthroughs, the Antikythera mechanism is still incomplete. Only one-third of the original device, split into 82 fragments, has been recovered. Freeth and his colleagues have since revealed its use of exeligmos cycles to adjust eclipse predictions, and proposed a comprehensive model that includes planetary motion tracking via epicyclic gearing described in surviving inscriptions.

But the story took a controversial turn in 2024, when physicist Graham Woan of the University of Glasgow published a statistical analysis in The Horological Journal. Using Bayesian inference, he and colleague Joseph Bayley studied a fragmented calendar ring believed to lie behind the mechanism’s main dial. Based on the spacing of 80 visible holes, they calculated that the ring most likely had 354 holes, suggesting it followed a lunar calendar.

This directly challenged the prevailing belief that the calendar was solar, with 365 holes. Woan’s analysis showed it was “299 times more likely” that the original count was 354. The finding stirred backlash from Freeth, who dismissed it as “just wrong,” arguing that a “crude lunar calendar” contradicted the sophistication of the device’s other components.

Nevertheless, Woan stands by the result, admitting assumptions may need refining but defending the approach: “If the observations are strong and constraining enough… the observations will drag you to the truth—even if it drags you there kicking and screaming.”

As it stands, the Antikythera mechanism continues to captivate. It represents not just the mechanical genius of Ancient Greece, but also the enduring power of scientific curiosity, debate, and rediscovery. After more than a century of study, it remains one of the greatest technological puzzles ever unearthed.