19th-century German businesspeople

Wilhelm Emil Fein (16 January 1842 – 6 October 1898) was a German inventor. He invented the worldwide first portable electric drill.

Hermann Julius Grüneberg (11 April 1827 – 7 June 1894) was a German chemist and inventor, and together with Julius Vorster the founder of the Chemische Fabrik Kalk.

Robert Bosch (23 September 1861 – 12 March 1942) was a German industrialist, engineer and inventor, founder of Robert Bosch GmbH.

August Thyssen (German: [ˈaʊɡʊst ˈtʏsn̩]; 17 May 1842 – 4 April 1926) was a German industrialist, founder and controlling shareholder of Thyssen & Co (presently ThyssenKrupp). He was a prominent member of the Thyssen family.

Friedrich Bayer (born Friedrich Beyer, 6 June 1825 in Barmen now Wuppertal – 6 May 1880 in Würzburg) was the founder of what would become Bayer, a German chemical and pharmaceutical company. He founded the dyestuff factory Friedrich Bayer along with Johann Friedrich Weskott in 1863 in Elberfeld, a flourishing city in the early industrialised region of the Wuppertal or Wupper Valley.

Friedrich Bayer changed the spelling of his surname from Beyer in his early twenties, due to the publicity gained by a fraudulent merchant from Leipzig bearing the same name. Friedrich Beyer from Barmen feared that the bad reputation of his namesake could damage his business and consequently changed his surname to Bayer.

Carl Zeiss (German: [kaʁl ˈtsaɪs]; 11 September 1816 – 3 December 1888) was a German scientific instrument maker, optician and businessman. In 1846 he founded his workshop, which is still in business as Carl Zeiss AG. Zeiss gathered a group of gifted practical and theoretical opticians and glass makers to reshape most aspects of optical instrument production. His collaboration with Ernst Abbe revolutionized optical theory and practical design of microscopes. Their quest to extend these advances brought Otto Schott into the enterprises to revolutionize optical glass manufacture. The firm of Carl Zeiss grew to one of the largest and most respected optical firms in the world.

Nicolaus August Otto (10 June 1832, Holzhausen an der Haide, Nassau – 26 January 1891, Cologne) was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine. The Association of German Engineers (VDI) created DIN standard 1940 which says "Otto Engine: internal combustion engine in which the ignition of the compressed fuel-air mixture is initiated by a timed spark", which has been applied to all engines of this type since.