from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
LETTER OF CREDENCE, international law. A written instrument addressed by the
sovereign or chief magistrate of a state, to the sovereign or state to whom
a public minister is sent, certifying his appointment as such, and the
general objects of his mission, and requesting that full faith and credit
may be given to what he shall do and say on the part of his court.
2. When it is given to an ambassador, envoy, or minister accredited to
a sovereign, it is addressed to the sovereign or state to whom the minister
is delegated in the case of a charge d'affaires, it is addressed by the
secretary or minister of state charged with the department of foreign
affairs to the minister of foreign affairs of the other government. Wheat.
International Law, pt. 3, c. 1, Sec. 7; Wicquefort, de l'Ambassadeur, l. 1,
Sec. 15.