Nikolaus August Otto (10 June 1832, Holzhausen an der Haide, Nassau - 26 January 1891, Cologne) was the German engineer of the first internal-combustion engine to efficiently burn fuel directly in a piston chamber. Though the concept of four strokes, with the vital compression of the mixture before ignition, had been invented and patented in 1861 by Alphonse Beau de Rochas, Otto was the first to make it practical.