I read that there were already two threads devoted to the amazing invention of the Middle Ages and the 18th century, but it seems that the Greeks did much more than that many centuries earlier.
This is a museum website dedicated to the amazing technological or mechanical advances of the ancient Greeks.
It seems that their engineers had discovered the principle of the steam engine and were able to manufacture machines that could have revolutionized the history of humanity such as, for example, a kind of analog mechanical computer and many others amazing inventions...

http://kotsanas.com/gb/museum.php

On this same website, the exhibition of these inventions.
http://kotsanas.com/gb/categories.php

Kind regards,
Abelard

While the ancient Greeks (and accordingly the Romans) seem to have knowledge of rudimentary steam-powered devices, I have always felt that it was their reliance on slavery that precluded the development of these amusing and interesting 'toys' into more useful machines. In short they had little incentive to develop steam engines. Or to put it yet another way: there was absolutely no reason to develop steam engines to drain deep mines, mass-produce cloth, forge iron bars, or power ships; when you already have thousands of slaves who can do, and already do, that sort of work. Furthermore an ancient Greek steam-powered industrial revolution would probably have been stymied by a lack of fuel: much of the ancient Hellenic forest had already been felled centuries earlier and Greece has few deposits of coal.