The Antikythera Mechanism

This machine has the oldest known complex gear mechanism and is sometimes called the first known analog computer, although the quality of its manufacture suggests that it may have had undiscovered predecessors during the Hellenistic Period. 

It appears to be constructed upon theories of astronomy and mathematics developed by Greek astronomers and is estimated to have been made around 100 BC. In 1974, British science historian and Yale University Professor Derek de Solla Price concluded from gear settings and inscriptions on the mechanism's faces that the mechanism was made about 87 BCE and was lost only a few years later.

It is believed the mechanism was made of a low-tin bronze alloy (95% copper, 5% tin), but the device's advanced state of corrosion has made it impossible to perform an accurate compositional analysis. All of the mechanism's instructions are written in Koine Greek and the consensus among scholars is that the mechanism was made in the Greek-speaking world.