The Marquis de Jouffroy d'Abbans demonstrated on 15 July 1783 that the Pyroscaphe, a 45-meter paddle steamer, could sail upstream on the Saône for fifteen minutes before thousands of spectators. It is the first witnessed, verified demonstration of a self-propelled steamboat. Despite presenting the project to the Académie des Sciences with documented evidence, the institution blocked his patent in favor of a rival. The French Revolution and exile ruined his commercial prospects. The historical canon attributes the invention of the steamboat to Robert Fulton (1807), twenty-four years later, whose vessel was the first to operate commercially but not the first documented functional demonstration.