In 1909, the International Opium Commission was founded, and by 1914, 34 nations had agreed that the production and importation of opium should be diminished. In 1924, 62 nations participated in a meeting of the Commission. Subsequently, this role passed to the League of Nations, and all signatory nations agreed to prohibit the import, sale, distribution, export, and use of all narcotic drugs, except for medical and scientific purposes. This role was later taken up by the International Narcotics Control Board of the United Nations under of the Single Convention on Narcotic Drugs, and subsequently under the Convention on Psychotropic Substances. Opium-producing nations are required to designate a government agency to take physical possession of licit opium crops as soon as possible after harvest and conduct all wholesaling and exporting through that agency.