Legalisation of documents
Bulgarian authorities and the authorities in other countries need to be certain about the status of each other's documents. It is often difficult to establish that status. It is impossible to know precisely who the authorizied officials in a country are, what powers they have, and what a particular document ought to look like.
Legislation confirms that a document was issued by someone with the authority to issue it, and that the signatures it bears are genuine. Some documents need to be signed by several different authorities in order to be legalized. This is called the legalisation chain.
Some countries have entered into agreements that streamline the legalisation chain. This means that certain documents from one of the contracting states may be used in another contracting state with only a single legalisation or even none at all (mainly within Europe).