Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is considered the starting point of modern organic chemistry. The Wöhler synthesis is of great historical significance because for the first time an organic compound (urea) was produced from inorganic precursors (the salt ammonium cyanate). This finding contradicted the then-mainstream theory vitalism, which stated that organic matter possessed a special force or vital force inherent to all things living. Prior to Wöhler's experiment, a sharp boundary was thought to separate organic and inorganic compounds.
^J. J. Berzelius "Lehrbuch der Chemie," 1st ed., Arnoldischen Buchhandlung, Dresden and Leipzig, 1827. ISBN1-148-99953-1. Brief English commentary in English can be found in Bent Soren Jorgensen "More on Berzelius and the vital force" J. Chem. Educ., 1965, vol. 42, p 394. doi:10.1021/ed042p394
^Dan Berger, Bluffton College, analysis of varying inappropriate definitions of the inorganic-organic distinction: Otherwise consistent linked material differing from current article in downplaying the carbon present vs carbon absent distinctive: 
^Newman, D. K.; Banfield, J. F. (2002). "Geomicrobiology: How Molecular-Scale Interactions Underpin Biogeochemical Systems". Science. 296 (5570): 1071–1077. doi:10.1126/science.1010716. PMID12004119.
^May, Paul. "Urea". Molecules in Motion. Imperial College London. Archived from the original on 2015-03-17.