Council of Trent: Session XIII, Reformation, Chapter VI

CHAPTER VI. A bishop shall not be personally cited, save in a case involving deposition, or deprivation.

And whereas the subjects of a bishop, even though they have been justly chastened, do often nevertheless bear him a violent hatred, and, as if they had suffered some wrong at his hands, object false accusations against him, in order that they may annoy him by whatsoever means lie in their power,-the fear which annoyance doth for the most part render the bishop more backward in inquiring into and punishing delinquencies; therefore, that a bishop may not be compelled-both to his own great inconvenience and that of his Church-to abandon the flock entrusted to him, and that he may not be forced-not without the diminution of the episcopal dignity-to wander from place to place, (the Synod) hath thus ordained and decreed: That a bishop, even though he be proceeded against ex officio, or by way of inquiry, or denunciation, or accusation, or in any other way whatsoever, shall not be cited or warned to appear in person, except for a cause for which he might have to be deposed from, or deprived of, his office.

Translation: J. Waterworth, The Canons and Decrees of the Council of Trent (1848), Hanover Historical Texts Project transcription (1995).