21 And now, venerable brethren, Our thoughts and letters desire to turn to you that We may again announce to you and again share with you the exceeding joy which We feel on account of the determinations which have been publicly entered into in that empire with regard to slavery. If, indeed, it seemed to Us a good, happy, and propitious event, that it was provided and insisted upon by law that whoever were still in the condition of slaves ought to be admitted to the status and rights of free men, so also it conforms and increases Our hope of future acts which will be the cause of joy, both in civil and religious matters. Thus the name of the Empire of Brazil will be justly held in honor and praise among the most civilized nations, and the name of its august emperor will likewise be esteemed, whose excellent speech is on record, that he desired nothing more ardently than that every vestige of slavery should be speedily obliterated from his territories. But, truly, until those precepts of the laws are carried into effect, earnestly endeavor, We beseech you, by all means, and press on as much as possible the accomplishment of this affair, which no light difficulties hinder. Through your means let it be brought to pass that masters and slaves may mutually agree with the highest goodwill and best good faith, nor let there be any transgression of clemency or justice, but, whatever things have to be carried out, let all be done lawfully, temperately, and in a Christian manner. Is is, however, chiefly to be wished that this may be prosperously accomplished, which all desire, that slavery may be banished and blotted out without any injury to divine or human rights, with no political agitation, and so with the solid benefit of the slaves themselves, for whose sake it is undertaken.
Source: In Plurimis (Vatican.va)