Well, I’ve often asked students when the first working “computers” were created, and watched their interest when I tell them about the Difference Engine of Babbage (Designed 1821-1833, first constructed 1837-1843 by Georg & Edvard Scheutz, based on Babbage’s design, but their own implementation) [Blaauw & Brooks, Computer Architecture, spring 1995 draft, and the Wikipedia]. Babbage’s work was based on ideas from Johann H. Muller in the 1780’s. However, I saw a blurb on Slashdot today that pushes the date of possible computers way back. I was unaware of the Antikythera mechanism, which is apparently an ancient Greek analog computer designed for celestial calculations. There is now a model (a best guess, of course) that has been constructed and is on display in Athens. Fascinating!