The earliest bicycles had no integrated means of propulsion - being essentially unpowered seated 'scooters'. The invention of the 'crank' - in other words the attachment of powering pedals to the wheel - appears to be a lost historical event :

Its early history is complex and has been shrouded in some mystery, not least because of conflicting patent claims: all that has been stated for sure is that a French metalworker attached pedals to the front wheel; at present, the earliest year bicycle historians agree on is 1864. The identity of the person who attached cranks is still an open question at International Cycling History Conferences (ICHC). The claims of Ernest Michaux and of Pierre Lallement, and the lesser claims of rear-pedaling Alexandre Lefebvre, have their supporters within the ICHC community."

Source : Wikipedia