Precursors to the modern bicycle first appeared 190 years ago. It wasn't until the 1890's, however, that bicycles began resembling what we have today, with the advent of pneumatic tires, chain-driven "safety bicycles," and free wheels. Rudimentary derailleurs, which are the transmission apparatus on most contemporary multi-speed bicycles, were also in development at this time in England but did not have much success. Not only was popular sentiment divided on the merits of bicycles having multiple speeds (variable gear ratios were seen as appropriate for sissies and the elderly), but a competing technology using gears within the bicycle hub was more successful commercially.
Paul de Vivie was such an avid cyclist that he quit his profession and devoted his time to cycling, writing for his own magazine about the sport (pen name: "Velocio") and improving upon existing bicycle designs. De Vivie was convinced that bicycles needed multiple gear ratios, so he combined his work of adding sprockets to bicycle chain wheels with the designs earlier developed by English inventors. While at the turn of the century the English cycle industry was far more advanced than France's, English derailleur systems weren't seeing any further progression. In 1906, de Vivie's work paid off with a four-speed bicycle driven by a derailleur system that could be operated without the rider dismounting.
Velocio's effort would not have been as notable had he not devoted so much of his time to marketing the derailleur to the French Public. French personalities in cycling decried variable gears, especially their use in races. De Vivie would not back down; he sponsored riders in races to prove the superiority of multiple gears. He also used his magazine, Le Cycliste, to tell stories of extended bicycle tours through the countryside, made enjoyable by the ease of which one could cycle into the wind and over hills once the limitations of a single gear were overcome.
Anyone who has a bicycle with multiple speeds can appreciate de Vivie's contribution to cycling. While his early derailleur systems do not resemble the derailleurs found on bikes made in the last 60 + years, his were the first to demonstrate that such a transmission system is not only mechanically viable, but for most purposes superior to the alternatives.