Throughout the history of
sovereign states,
diplomats have enjoyed a special status. The principle of
diplomatic immunity dates back to ancient times, when Greek and Roman governments granted special status to envoys. This basic concept has endured and continued to evolve over the centuries, remaining an important element of foreign relations up to the present day. Their function to negotiate agreements between states demands certain special privileges. An envoy from another nation is traditionally treated as a guest, their communications with their home nation treated as confidential, and their freedom from coercion and subjugation by the host nation treated as essential. The first attempt to codify
diplomatic immunity into
diplomatic law occurred with the
Congress of Vienna in 1815. This was followed much later by the Convention regarding Diplomatic Officers (Havana, 1928). The present treaty on the treatment of diplomats was the outcome of a draft by the
International Law Commission. The treaty was adopted on 18 April 1961, by the United Nations Conference on Diplomatic Intercourse and Immunities held in
Vienna,
Austria, and first implemented on 24 April 1964. The same Conference also adopted the Optional Protocol concerning Acquisition of Nationality, the Optional Protocol concerning the Compulsory Settlement of Disputes, the Final Act and four resolutions annexed to that Act. One notable aspect which arose from the 1961 treaty was the establishment of the
Holy See's diplomatic immunity status with other nations. Two years later, the
United Nations adopted a closely related treaty, the
Vienna Convention on Consular Relations. ==Summary of provisions==