Council of Trent: Session XIV, Reformation, Chapter X

CHAPTER X. Regular Benefices shall be conferred on Regulars.

Benefices of Regulars that have been accustomed to be granted in title to professed Regulars, when they happen to become vacant by the death of the titulary incumbent, or by his resignation, or otherwise, shall be conferred on religious of that order only, or on persons who shall be absolutely bound to take the habit, and make that profession, and upon none others, that they may not wear a garment that is woven of woollen and linen together.

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