CREDENTIALS, LETTERS OF. - This is the proper designation of the formal act by which one diplomatic agent (v.) to another.
Letters of credence are addressed from head of State to head of State when the diplomatic agent is an ambassador or a minister plenipotentiary or resident; from foreign minister to foreign minister when the matter concerns a chargé d’affaires. The agent is installed in his functions by the presentation of the letters of credence (which takes place with particular formalities prescribed by diplomatic protocol), and from that moment he must be regarded as an organ performing acts internationally attributable to the accrediting State.
When the agent is recalled by his government, he presents, usually with the same formalities, the “letters of recall,” receiving, from the competent organ of the State to which he is accredited, the lettres de récréance.