In 1900 some sponge divers off the Greek island 'Antikythera' found a shipwreck containing a wooden box the size of, or smaller than, a modern laptop carrying bag.
Inside was a mechanism, albeit corroded, of surprising complexity. In 1974, after Xray analysis, a 70-page paper was published in Nature and it was seen that the mechanism simply was not explained by our accepted history. From 2005 dedicated research using modern techniques and computer simulation showed that the term 'surprising complexity' is an understatement! Now dated as being from around 100-200 BC, it was a clockwork device comprising thirty meshing bronze gears. In contrast, a 'modern' mantelpiece wind-up carriage clock has probably only about seven. To emphasise the historical context, this is a century or two before Jesus...
Models and simulations have been made and this item turns out to describe (that is, predict), month, day, hour of an eclipse, also accounting for leap years. It could also predict the positions of the sun and moon against the zodiac, and a black and white stone turns to show the moon's phase on a given date! It could also show the astronomical positions of the solar system planets: Mercury, Venus, Mars, Jupiter and Saturn. Major athletic competitions (such as the Olympics) every two or four years were also indicated. In modern terminology it could correctly be dubbed a mechanical 'Analogue Computer'.
The mechanical design actually took account of the irregular (elliptical) motion of the moon, though many experts even now still believe that the Ancients did not have such knowledge. The words of Sherlock Holmes come to mind: 'Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.'
This is left for the reader to ponder!
An online search for more information is rewarding and is recommended because the true wonder of this device is astounding when one sees it in action!
'In search of lost time'(Nature)
'Advanced Imaging Reveals a Computer 1,500 Years Ahead of Its Time'
Antikythera: A 2,000-year-old Greek computer comes back to life