Pages that link here:
History of tricycle began much before first two-wheeled bicycles arrived on the market. More than century earlier, first tricycles with hand-powered propulsion mechanisms marked the beginning of the history of tricycles.
History of bicycle started with the first two wheeled transportation device made by German Baron Karl Drais in early 19th century. His simple Dandy Horse design provided inspiration to countless other inventors who very quickly created modern bicycles.
The early history of bicycles was a birthing ground of many interesting transportation devices that resembled modern bicycles. Without access to chain drive systems, those early velocipedes came in many shapes and sizes.
Unicycle is a specific type of bicycle whose history started shortly after introduction of the popular penny-farthing bicycles who managed to train drivers how to easily balance their weight by sitting on one big wheel. Here you can read more about history of unicycle.