Paul VI: Mysterium Fidei

This particular encyclical was issued by Pope Paul in September of 1965. It was written with "serious pastoral concern and anxiety" and laid down the doctrine of the Eucharist backed by papal authority way before JPII chimed in with Dominicae Cenae and Ecclesia de Eucharistia.

However, like most of Paul VI's good efforts, it was either ignored or blasted by a large number of folks in and out of the Church. If you read some of the Vatican II histories I've mentioned thus far, you'll find that Mysterium Fidei went off like theological dynamite. Soooo many progressives thought that Vatican II was going to give them a leg up in getting rid of all that Real Presence and transubstantiation stuff. Robert Brown, writing his book The Ecumenical Revolution, sounds like he is about to cry when discussing it. Ditto for guys like Kung. After all, the worst thing for them is a forceful presentation of the Faith.

Here's the deal, as clearly laid out by Pope Paul:

To confirm what we have said by examples, it is not allowable to emphasize what is called the "communal" Mass to the disparagement of Masses celebrated in private, or to exaggerate the element of sacramental sign as if the symbolism, which all certainly admit in the Eucharist, expresses fully and exhausts completely the mode of Christ's presence in this sacrament. Nor is it allowable to discuss the mystery of transubstantiation without mentioning what the Council of Trent stated about the marvelous conversion of the whole substance of the bread into the Body and of the whole substance of the wine into the Blood of Christ, speaking rather only of what is called "transignification" and "transfiguration," or finally to propose and act upon the opinion according to which, in the Consecrated Hosts which remain after the celebration of the sacrifice of the Mass, Christ Our Lord is no longer present.

Take time to go through the whole thing.