Ideally a 'Motorcycle' is any type of powered bicycle.
For the sake of simplicity, we consider the widest known and most popular definition of a motorcycle - a bicycle having an internal combustion engine.
Reitwagen had an internal combustion engine powered by gasoline.
The first patent describing Reitwagen is DE36423C. Hence effectively this patent can be called the basic or the original patent of motorcycle.
Reitwagen had an innovative high-speed single-cylinder engine, patented on April 3, 1885 and called "grandfather clock engine".
The original Reitwagen was destroyed in the Cannstatt Fire in the DMG Seelberg-Cannstatt plant in 1903. Now only replicas exist in several places.