At the super table last night the question came up: how early in history could one have made a bicycle? As a history buff I knew that the first two wheeled "hobby horses" date back to the early 19th century. They sort of look like bicycles, but lack the pedal powered aspect that I'd consider as essential aspect to the modern bicycle. Oddly, there's nothing in that technology that couldn't have been done hundreds of years earlier. Once you've made a reasonable wheel, you could have made one of those 1820's hobby horses. Anyone who had made a chariot could have made an hobby horse. It's actually surprising that one in ancient times did this (at least that we know of).

But what we were thinking of was something that worked more like a modern bike. With pedal power and mechanical advantage and roughly equal wheel sizes. Something that you hop on and feel like it was a bike as you know it, maybe a metal shod, wooden wheel fixie kind of thing--but a modern bicycle conceptually, only with the technology that was available at the time.

Yes, I knew that direct pedals were put on the front wheel of the hobby horse concept by the middle of the 19th century, and eventually we got the high front wheel variation of that. But what I wondered as we talked, was how early could humans have had the technology to make the equivalent of a modern (albeit wooden wheeled) fixie? Chains (or belts I suppose) would have been key. Much earlier than 1800 for something that could have been practically built and used?