Council of Trent: Session XIII, Eucharist, Chapter VI

CHAPTER VI. On reserving the Sacrament of the sacred Eucharist, and bearing it to the Sick.

The custom of reserving the holy Eucharist in the sacrarium is so ancient, that even the age of the Council of Nicaea recognised that usage. Moreover, as to carrying the sacred Eucharist itself to the sick, and carefully reserving it for this purpose in churches, besides that it is exceedingly conformable to equity and reason, it is also found enjoined in numerous councils, and is a very ancient observance of the Catholic Church. Wherefore, this holy Synod ordains, that this salutary and necessary custom is to be by all means retained.

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