|a fragment of the Antikythera mechanism|
The photo above doesn't look like any part of the history of computers. Do they date back a millennia to a time of analogue devices?
Some claim that the world’s oldest known “computer” is the Antikythera mechanism. This now badly-corroded bronze artifact was found in 1901 in the remains of a shipwreck near the Mediterranean island of Antikythera.
In the 1970s, using radiography, it was determined that the device is a complex mechanism with at least 30 gear wheels (some have certainly been lost).
It is more accurate to say that it is a mechanical calculator than computer because it can't be "reprogrammed."
That doesn't diminish that is is a very impressive Greek astronomical device for its time, which was around 100 BCE.
About the size of a shoe box, with dials front and back faces, it could be used to show using pointers where the sun and moon were in the sky, the current phase of the moon, the 19-year cycle of lunar months, the 18.2 year Saros cycle of lunar and solar eclipses and probably other celestial events.
The Antikythera Mechanism Research Project in Greece is still discovering inscriptions that tell what stars were just becoming visible at different times of year.
Of course, these things were known at the time of the device. The Greek astronomer and mathematician Geminos had written about these things, but to build a mechanism to do the calculatons was extraordinary.
The presumed date of the shipwreck is around 60 BC, and the location of the shipwreck seems to point to the mechanism originating on the island of Rhodes, from where there is a contemporary historic record from the writer Cicero of such devices.