Council of Trent: Session XXV, Regulars and Nuns, Chapter XVIII

CHAPTER XVIII. No one shall, except in the cases by law expressed, compel a woman to enter a Monastery; or prevent her, if she desire to enter. The constitutions of the Penitents, or Convertites, shall all be preserved.

The holy Synod places under anathema all and singular those persons, of what quality or condition soever they may be, whether clerics or laymen, Seculars or Regulars, or with whatsoever dignity invested, who shall, in any way whatever, force any virgin, or widow, or any other woman whatsoever,--except in the cases provided for by law,--to enter a convent against her will, or to take the habit of any religious order, or to make her profession; as also all those who lend their counsel, aid, or countenance thereunto ; and those also who, knowing that she does not enter into the convent voluntarily, or voluntarily take the habit, or make her profession, shall, in any way, interfere in that act, by their presence, or consent, or authority.

It also subjects to a like anathema those who shall, in any way, without a just cause, hinder the holy wish of virgins, or other women, to take the veil, or make their vows. And all and singular those things which ought to be done before profession, or at the profession itself, shall be observed not only in convents subject to the bishop, but also in all others whatsoever. From the above, however, are excepted those women who are called penitents, or convertites; in whose regard their constitutions shall be observed.

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