Greece ? Imagine tossing a top-notch laptop into the sea, leaving scientists from a foreign culture to scratch their heads over its corroded remains centuries later.

A Roman shipmaster inadvertently did something just like that 2,000 years ago off southern Greece, experts said Thursday.

They claim to have identified a handful of puzzling metal scraps found in a ship wreck as the earliest known mechanical computing device, which pinpointed astronomical events.

A team including British, Greek and U.S. scientists used specially developed X-ray scanning and imaging technology to analyze the corroded bronze, revealing hidden machinery and a form of written user’s manual.

Known as the Antikythera Mechanism – from the island off which the Roman ship sank – the assemblage of cogs and wheels looks like the innards of a very badly maintained grandfather clock. But the first clockwork devices appeared more than a thousand years later in Western Europe.

The box-shaped mechanism – the size of office paper and operated with a hand-crank – could predict an eclipse to a precise hour on a specific day.