The synthesis of the first organophosphate cholinesterase inhibitor (tetraethyl pyrophosphate, TEPP) is credited to the French organic chemist Philippe de Clermont (1831-1921) and to the Russian chemist Wladimir P. Moshnin from Moscow, both working in the laboratories of Adolphe Wurtz in Paris. In his publications de Clermont describes however not only the TEPP synthesis but also that of the related compound triethyl phosphate (TEP). TEP was previously synthesized by the Swiss chemist Franz Anton Voegeli (1825-1874), working in the laboratory of Gustav Magnus in Berlin. While TEPP is a potent organophosphate cholinesterase inhibitor with an IC50 in the low nanomolar range, TEP has no anticholinesterase activity up to millimolar concentrations. Therefore de Clermont and Moschnin are indeed the fathers of the first organophosphate cholinesterase inhibitor (TEPP), but are not entitled to claim paternity of the first compound in the class of phosphoric acid esters (TEP), an honor which belongs to Franz Anton Voegeli.