Motrice Pia
The Motrice Pia was an early three-wheeled vehicle, introduced by Italian Enrico Bernardi, and credited as the first motorcycle by sources such as the Enciclopedia Italiana di Scienze, Lettere [ed Arti]. The exact year of introduction depends on which one of the following milestones one considers: the demonstration of a gasoline engine in 1882–1884, the application of the engine to a child's tricycle in 1884, the application of this engine to a motorized tricycle in 1893, or the mounting of the motor behind a bicycle on a one-wheel trailer via chain drive creating a "motorcycle" in 1894.