When was the first ten speed bicycle made?

Answer 1

Short answer: 1949.

Long answer: Bikes have had external multiple gears since the early 1900's (designs and patents go back to late 1800's!), starting off using chain-stay mounted rods, like the "Osgear", "Vittoria Margherita" and "Campagnolo Cambio Corsa", to push the chain across to different rear cogs.

Cable operated parallelogram derailleurs were invented in 1938 by the French company "Simplex". In 1949 Campagnolo refined this design with their "Gran Sport" rear derailleur. Of course, you can't have 10 speeds unless you can change your front chainrings. Also in 1948, Campagnolo invented the front derailleur and thus the dawn of the "10 speed", which became the "12 speed", "14 speed", "16 speed", etc.

Suntour improved and patented the derailleur design in 1964 with the "slant-parallelogram" which allowed for easier shifting, but patents expired so this design became wide spread and is what we use for derailleurs today. Shimano came out with SIS index shifting (1985, I believe) which required the user to buy all Shimano components for their drive train essentially crushing almost all of the competition (Suntour and Campagnolo had indexing drivetrains, but didn't monopolize on the technology the way Shimano did) in the bicycle component manufacturing field.