Legalization certifies the origin of a document. It is an official confirmation of the veracity of the signature, stamp or seal of the official who signed the document.
A country may also be bound by a legalisation treaty that contains agreements on how countries accept official documents from each other. A large number of countries are thus bound by the Hague Apostille Convention of 5 October 1961. In this case, only one legalisation is necessary by means of a stamp bearing the mention Apostille.