Various derailleur systems were designed and built in the late 1800s. The French bicycle tourist, writer and cycling promoter Paul de Vivie, aka Velocio, (1853-1930) invented a two speed derailleur in 1905 which he used on extensive forays into the Alps. Some early designs used a system of rods to move the chain onto various gears. Derailleurs did not become common road racing equipment until 1938 when Simplex introduced their cable shifted derailleur. In the early 1950s the cable-operated, parallelogram variety used on today's bicycles was introduced by Tullio Campagnolo, who also invented the quick release skewer for attaching the wheels. With Campagnolo's introduction of the parallelogram front derailleur, Campagnolo became the standard for high quality derailleurs and for several decades true racing bicycles were all campy, meaning that the derailleurs, shifters, hub and chain were all manufactured by the Campagnolo company. The major innovations since then have been the gradual increase in the number of gears on both hubs (on racing bicycles, 11-gear rear hubs are appearing as of 2003, and most current bicycles have at least three front gears), and tensioning systems designed for one-push gear changes. Derailleur gears are the most common type of gears used on bicycles today.
The alternative type of gear system used on bicycles are Hub gears.
Fixed gear cyclists eschew the use of derailleurs favoring a simpler, more rugged configuration with fewer, or zero, cables. They enjoy quoting Henri Desgrange, the founder of the Tour de France: