In most countries, the language used for celebrating the Tridentine Mass was and is Latin. However, in Dalmatia and parts of Istria in Croatia, the liturgy was celebrated in Church Slavonic, and authorisation for use of this language was extended to some other Slavic regions between 1886 and 1935.
After the publication of the 1962 edition of the Roman Missal, the 1964 Instruction on implementing the Constitution on Sacred Liturgy of the Second Vatican Council laid down that "normally the epistle and gospel from the Mass of the day shall be read in the vernacular". Episcopal conferences were to decide, with the consent of the Holy See, what other parts, if any, of the Mass were to be celebrated in the vernacular. Outside the Roman Catholic Church, the vernacular language was introduced into the celebration of the Tridentine Mass by some Traditional Catholics.
Occasionally the term "Gregorian Rite" is used when talking about the Tridentine Mass, as is, more frequently, "Tridentine Rite". Pope Benedict XVI declared it inappropriate to speak of the versions of the Roman Missal of before and after 1970 as if they were two rites. Rather, he said, it is a matter of a twofold use of one and the same rite.
Within the Eastern Byzantine Churches the mass is known as the Divine Liturgy of Saint Gregory the Great.
Traditionalist Catholics like ourselves, whose best-known characteristic is an attachment to the Tridentine Mass, frequently refer to it as the "Traditional Mass" or the "Traditional Latin Mass". We describe as a "codifying" of the form of the Mass the preparation of Pius V's edition of the Roman Missal, of which he said that the experts to whom he had entrusted the work collated the existing text with ancient manuscripts and writings, restored it to "the original form and rite of the holy Fathers" and further emended it. To distinguish this form of Mass from the Mass of Paul VI, traditionalist Catholics sometimes call it the "Mass of the Ages", and say that it comes down to us "from the Church of the Apostles, and ultimately, indeed, from Him Who is its principal Priest and its spotless Victim".