Council of Trent: Session 21
Chapter 5
Bishops shall be able to form perpetual unions, in the cases by law permitted.
In order, also, that the state of those churches, wherein the sacred offices are administered unto God, may be maintained according to their dignity, the bishops, even as the delegates of the Apostolic See, may, according to form of law, make unions in perpetuity—without prejudice, however, to the incumbents—of any parochial churches whatsoever, and of those wherein baptism is administered, and of other benefices with or without cure, with (other) cures, on account of the poverty of those churches, and in the other cases by law permitted; even though the said churches, or benefices, be generally or specially reserved, or in what way soever applied: the which unions shall not be capable of being revoked, by virtue of any provision whatever, not even on account of any resignation, or derogation, or suspension.
Chapter 6
To ignorant Rectors, Vicars shall be, for the time being, deputed with a portion of the fruits; those continuing to give scandal may be deprived of their benefices.
Forasmuch as illiterate and unskilful rectors of parish churches are but little fit for the sacred offices; and others, by reason of the turpitude of their lives, rather destroy than edify; the bishops, even as the delegates of the Apostolic See, may depute to the said illiterate and unskilful rectors, if they be otherwise of a blameless life, coadjutors, or vicars for the time being, and assign the same a part of the fruits for their sufficient maintenance, or provide for them in some other manner, setting aside any appeal or exemption whatsoever. But, those who live shamefully and scandalously, they shall, after having first admonished them, restrain and punish; and, if they shall still continue incorrigible in their wickedness, they shall have power to deprive them of their benefices, according to the constitutions of the sacred canons, setting aside every exemption or appeal whatsoever.
Chapter 7
Bishops shall transfer, together with their obligations, churches which cannot be restored; others they shall cause to be repaired.
Whereas, also, very great care ought to be taken, lest those things which have been dedicated to sacred services, may, through the injury of time, cease to be so employed, and pass from the memory of men; the bishops, even as the delegates of the Apostolic See, may transfer simple benefices—even those that are under a right of patronage—from churches which have fallen into ruin by age, or otherwise, and which cannot, by reason of the poverty thereof, be restored, to the Mother Churches, or others of the same or neighbouring places, as they shall judge fit, after having summoned those who are interested therein; and they shall raise, in the said churches, altars, or chapels, under the same invocations; or transfer them, with all their emoluments and with all the obligations that were imposed on the former churches, to altars or chapels already erected. But, as regards parish churches which have thus fallen into decay, they shall, even though they be under a right of patronage, make it their care that they be repaired and restored, out of any fruits and proceeds whatever, in any way belonging to the said churches; and if those resources should not be sufficient, they shall compel, by all suitable means, the patrons and others who receive any fruits derived from those churches, or, in their default, the parishioners, to provide for the aforesaid repairs; setting aside every appeal, exemption, or reservation whatsoever. But if they should be all too poor, those churches shall be transferred to the Mother Churches, or to the neighbouring churches, with power to convert both the said parish churches and others that are in ruins, to profane, though not to sordid uses; a cross, however, being erected there.