A large number of countries all over the world have joined a treaty that greatly simplifies the authentication of public documents to be used abroad. This treaty is called the Hague Convention of October 1961 Abolishing the Requirement of Legalisation for Foreign Public Documents. It is commonly known as the Apostille Convention. Where it applies, the treaty reduces the authentication process to a single formality: the issuance of an authentication certificate by an authority designated by the country where the public document was issued. This certificate is called an Apostille. The Apostille Convention has proven to be extremely useful and is applied millions of times each year throughout the world. It greatly facilitates the circulation of public documents issued by a country party to the Convention and that are to be used in another country also party to the Convention.