However, there are different perspectives on this:
* 1680: Christiaan Huygens built a gunpowder-powered engine, which could be considered a very early internal combustion engine.
* 1791: John Barber patented a gas turbine engine, which could also be considered a predecessor to the internal combustion engine.
* 1858: The "atmospheric gas engine" invented by Alphonse Beau de Rochas, though not physically built at the time, outlined the key principles of the four-stroke engine cycle.
While Lenoir's engine was the first to be commercially successful, the history of the internal combustion engine has a long and complex path with many contributors.
