Many years ago off the Greek Island of Antikythera sponge divers located several pieces that made up a very strange device comprised of thirty bronze gears. It has been studied and attempts to replicate the device have taken place in the years since, but it took the Antikythera Mechanism Research Project to use modern technology to determine the purpose of the device and to build an accurate replica.
Today it is believed the Antikythera Device is an analog computer. More than likely it was used to plot the orbits of planets, predict eclipses, and set the dates for the quadrennial Olympic games. There are several inscriptions on the device. One in particular refers to “Ispania” and is one of the earliest known text references to Spain.
Researchers believe the device dates to 100-150 B.C.
One theory is that the device was being transported to Rome to be part of a trumphal parade staged by Julius Ceasar when the boat that was carrying it sunk of the Greek Island.
This site and this site also have very detailed accounts of the Antikythera Device.