Before the 1970 revision of the Roman Missal, the Mass had, in the Roman Rite, only one Anaphora or Eucharistic Prayer, which was referred to as the Canon of the Mass. Since the revision, which made only minimal changes in the text, but somewhat more important changes in the rubrics, it is called Eucharistic Prayer I or the Roman Canon. In the Anglican Missal, it is called The Canon of the Roman Mass.
This article does not deal with the significance and history of this Eucharistic Prayer (see History of the Roman Canon), but only with the text and rubrics of the Canon from the Te Igitur to the final doxology, omitting consideration of the introductory dialogue, the preface and the Sanctus. These parts were not altered in 1970, except for the addition of further prefaces, generally taken from ancient sources.
In the Tridentine form of the Mass, the priest says this part of the Canon inaudibly, with only two exceptions: he speaks the phrase "Nobis quoque peccatoribus" in a slightly audible voice, and says or sings aloud the final phrase of the doxology, "per omnia saecula saeculorum", so as to let the server or the choir know when to say or sing "Amen". This silence on the priest's part is associated with the fact that, in the Tridentine Mass, the priest says all parts of the Mass (except such responses as "Et cum spiritu tuo" and "Amen") himself, even if the choir sings them also. It became customary for the priest, having himself said the "Sanctus" quickly, not to wait for the choir to finish singing, but to continue immediately, necessarily not aloud, the rest of the Canon.
This was not always so. The older Roman ordines state that originally "the priest did not begin the Canon until the singing of the Sanctus was over" (Mabillon: In ord. Rom. comm., XXI). And, even in the Tridentine period, when an ordination Mass was almost the only case of concelebration left in the West, all the concelebrants said the Canon together aloud. However, mystic reasons were attributed to the silent prayers of the Canon, as purely sacerdotal, belonging only to the priest, with the silence increasing reverence at the most sacred moment of the Mass and removing the Consecration from ordinary vulgar use.