Sign In

Communications of the ACM

Last Byte

Aftermath Impact

the Antikythera mechanism

Credit: Justin Henderson

With great foreboding, Andivius rushed toward the Amphitheatrum, terrified that dictator Lucius Cornelius Sulla might have ordered him there for purpose of supplicium, which could mean anything from supplication to execution. Rome had entered a period of deep uncertainty, decades before Caesar and Augustus established the Empire, and democracy was disintegrating into chaos that ironically the unstable Sulla had promised to reorganize.

"Ah, Andivius, ave atque vale!"

Horrors! Sulla had just spoken the equivalent of "hail and farewell," which he might well say to a servant who was about to be murdered for his poor quality of work.

"I am sending you on a glorious expedition, but first I must instruct you on the meaning of its goal. We all know that democracy was fatally erratic, so we need a new machinery of government, literally intellegentias artificialis, a set of machines that make decisions on the basis of strict rules."

Sulla then held up his pocket abacus, a Roman improvement over the Greek version of this already ancient calculating device, now used regularly by merchants and tax collectors. He explained a plan to create beside the Senate a new Laboratorium that would combine all the science and invention of Greece, Egypt, and the rest, to give Rome a vastly superior culture. So, Sulla ordered Andivius to sail the sea between Greece and Egypt, collecting artifacts that represented potentially great computational inventions, thereby assembling the equipment for aggressive analysis and innovation in the Laboratorium.

"Democracy was fatally erratic, so we need a new machinery of government, literally intellegentias artificialis."

Before dismissing Andivius, Sulla showed him why they were meeting at the Amphitheatrum, an open arena for gladiators and festivals. Music to excite the audience was provided by a complicated machine called a hydraulis, the ancient ancestor of Renaissance church organs. It was a very appropriate metaphor for the future of government, because slaves labored to pump air into a huge reservoir that was placed in a cistern of water. That had the effect of smoothing out the surges from slavish pumping and providing constant-pressure air for the organ's pipes, which were controlled by a musician operating a keyboard of large levers.

While ordinary people listened to the music of the hydraulis, Sulla imagined how the mechanism might be used to control the prices merchants charged for their goods. Every week, the government could state the price for many standard items, and merchants throughout the Roman Republic would charge exactly those amounts. How the hydraulis would contribute to that process was not yet clear, but Sulla suggested that a few hundred of these devices in the Laboratorium could calculate appropriate prices within the current government policy, while considering natural forces such as the seasons of the year.

Sulla placed Andivius in temporary command of his great yacht, named Publius after his grandfather, who ironically was an advocate for democracy, with Athens as its obvious first destination. Having some experience yachting, Andivius was able to direct its proletarian sailors, although he detected they sometimes followed their own instincts rather than his orders. The only literate member of the crew, Proditor, seemed interested in Sulla's project, so Andivius took him into Athens as his servant.

Their initial goal was collecting various clepsydra water clocks, which had different designs, especially in the feedback mechanism that regulated the flow of water. Sundials were a marvelous ancient invention, which both the Egyptians and Babylonians laid claim to. Their obvious defect is that they do not work at night, so some still-unidentified civilization invented clocks based on the slow dripping of water from one container to another. Also, except at the literal equinox, hours in the day as measured by sundials were longer in summer than in winter, given that there were always 12 hours from dawn to dusk. The clever Greeks noticed that time, as measured by water clocks, was not much more stable than when dictated by the sun. So, they invented a feedback device that controlled constant water drippage. Ctesibius, a Greek living in Egypt, perfected the clepsydra and invented the hydraulis.

While they were gathering clepsydras, Proditor mentioned that one of the collections they had visited included a very different device, apparently based on ideas about the use of compressed air, which had been developed by Ctesibius. Called an aeolipile, it was an engine that used steam to spin a part of the device around, visually dramatic but having no practical purpose. Proditor asked Andivius whether some of the devices they gathered might be adapted for social progress rather than governmental control. Andivius joked, "Oh, are you suggesting that we use hot steam rather than cool sails and enslaved oarsmen to move our Publius boat even faster?" Andivius laughed first, followed by Proditor.

He gave them the most marvelous computer of the ancient world, a complex system of gears that could predict the motions of the moon and planets.

After completing their collection of relics and documents in Athens, they headed for the island of Rhodes, which had recently become more culturally significant even than Athens. They visited Posidonius, who operated the leading school in the western world, had already done an exploratory tour around the Mediterranean, and had written a scientific analysis of how the movement of the Moon produced the complex tides in the sea. Under some political pressure and offered a decent price, he gave them the most marvelous computer of the ancient world, a complex system of gears that could predict the motions of the moon and planets. Greek inscriptions coded the signs of the zodiac and the months of the Egyptian year.

As Publius sailed away from Rhodes, south toward Alexandria in Egypt, where they hoped to find more relics left by the long-deceased Ctesibius, Andivius lectured Proditor about how the Roman government might use this astronomical device. For example, it could control the work by farmers, over the course of each year, following rules for their location and crops. Proditor seemed a bit distracted, and commented, "Yes, that is a crucial insight, sir. But I was thinking about what Posidonius said about the excellent computatra being developed on the nearby island of Antikythera. Shouldn't we stop there before going to antique Alexandria?" Andivius did not recall Posidonius mentioning Antikythera, but became convinced by Proditor's enthusiasm, so he ordered the crew to head westward rather than south.

The truth suddenly became clear approximately a mile from the island. Without any command from Andivius, the crew dropped the sails and prepared the two small dinghies used to reach land where no port existed. Proditor and two other members of the crew approached Andivius with daggers in their hands.

"Sorry about this," Proditor said, "but Antikythera has no computatra but instead is held by pirates. I'm not sorry that we must now sink this ship, so Sulla never learns what happened and comes after us in revenge."

Three stabs and Andivius was dead. Proditor and the other crewmen took whatever valuables they could loot but not any of the relics, which they considered valueless, and set fire to Publius. We do not know their fate when they attempted to join the Antikythera pirates, but the amazing astronomical device did survive. Nearly two thousand years later, in 1901, the real but incredible ancient computer now called the Antikythera Mechanism was accidentally discovered by divers in the shipwreck. Whether it could have saved Rome from its decline and fall remains a mystery.

Back to Top


William Sims Bainbridge ( is a sociologist who taught classes on crime and deviant behavior at respectable universities before morphing into a computer scientist, editing an encyclopedia of human-computer interaction, writing many books on things computational, from neural nets to virtual worlds to personality capture, then repenting and writing harmless fiction.

©2023 ACM  0001-0782/23/02

Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and full citation on the first page. Copyright for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or fee. Request permission to publish from or fax (212) 869-0481.

The Digital Library is published by the Association for Computing Machinery. Copyright © 2023 ACM, Inc.


No entries found

Sign In for Full Access
» Forgot Password? » Create an ACM Web Account
Article Contents: