Letter of credence

A letter of credence is a formal letter, usually sent by one head of state to another, that formally grants diplomatic accreditation to a named individual to be the sending country's ambassador in the receiving country. A letter of recall is the opposite, recalling an ambassador, either as a means of diplomatic protest (see letter of protest) or because the diplomat is being replaced by another envoy. Diplomatic letters are generally written in French (the lingua franca of diplomacy), unless the countries share the same official language.