A later form of ecclesiastical letter is that with which we are so familiar, the “letter dimissory.” This expression first occurs in Canon XVII. of the Council in Trullo. On this expression Suicer (Thesaurus, s.v. ἀπολυτικὴ) draws from the context the conclusion that “letters dimissory” were given only for permanent change of ecclesiastical residence, while, “letters commendatory” were given to those whose absence from their diocese was only temporary.