How did unicycling begin?
The accepted view is that the unicycle came from the penny-farthing bicycle, which had a large front wheel and a small rear wheel. The penny-farthing had cranks directly connected to the front axle. If a rider stopped quickly, the rear wheel would go up in the air as the rider moved forward a bit. Some riders no doubt found that they could ride a bit with the rear wheel up, and then decided to see how far they could go. Pictures of unicycles from the late 1800’s show big-wheeled unicycles, which would support the idea that the first unicycles came from penny-farthing bicycles. The Quebec Unicycle Association has a page in French discussing the origin of the unicycle which describes the same view (I think). The URL is http://www.gel.ulaval.ca/~stpier02/amq/homeangl.html.