Vienna Convention, amendment and codification of diplomatic law further developed by custom after the Congress of Vienna 1814/15. Completed on April 18, 1961 in Vienna after preliminary work done by the United Nations International Commission and put into force on April 24, 1964. The Vienna Convention governs diplomatic relations including privileges and immunities of diplomats. As of January 1, 1996 174 countries - almost the entire international community - were member states of the Vienna Convention. Similar regulations were set up in the Vienna Convention of Consular Relations on April 24, 1963, which came into force in 1967 and had been signed by 153 countries by January 1, 1996.