Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Seventh Ecumenical Council.  The Second Council of Nice.: Canon XII

Canon XII.

That a Bishop or Hegumenos ought not to alienate any part of the suburban estate of the church.

If bishop or hegumenos is found alienating any part of the farm lands of the bishoprick or monastery into the hands of secular princes, or surrendering them to any other person, such act is null according to the canon of the holy Apostles, which says:  “Let the bishop take care of all the Church’s goods, and let him administer the same according as in the sight of God.”  It is not lawful for him to appropriate any part himself, or to confer upon his relations the things which belong to God.  If they are poor let them be helped among the poor; but let them not be used as a pretext for smuggling away the Church’s property.  And if it be urged that the land is only a loss and yields no profit, the place is not on that account to be given to the secular rulers, who are in the neighbourhood; but let it be given to clergymen or husbandmen.  And if they have resorted to dishonest craft, so that the ruler has bought the land from the husbandman or cleric, such transaction shall likewise be null, and the land shall be restored to the bishoprick or monastery.  And the bishop or hegumenos doing this shall be turned out, the bishop from his bishoprick and the hegumenos from his monastery, as those who wasted what they did not gather.

Notes.

Ancient Epitome of Canon XII.

According to what seemed good to the Holy Apostles, any act of alienation of the goods of a diocese or of a monastery made by the bishop, or by the superior of the monastery, shall be null.  And the Bishop or Superior who shall have done this shall be expelled.

Van Espen.

As at the time of this Synod by the favour of kings and princes the way was frequently open to ecclesiastical dignities, clergymen might easily be induced through ambition to make over to princes some part of the Church’s possessions, if only by so doing they might arrive at the coveted preferment through their patronage, and then desiring to make good this simoniacal promise, they studied to transfer the church’s goods to their patrons; with regard to these the present decree of the synod was made.

But because human ambition is cunning, p. 564 and solicitously seeks a way of attaining its ends, ambitious clerics tried by various colouring to give a tone to and to palliate these translations of church-goods to princes and magistrates, so that they might attain to that they aimed at by the favour of said princes and magistrates.

Two such pretexts the synod exposes and rejects in the present canon.

This canon is found in the Corpus Juris Canonici, Pars II., Causa XII., Quæst. II., canon xix.