<P> The term Latin Mass refers to the liturgy of the Roman Catholic Mass celebrated in Latin . </P> <P> The term "Latin Mass" is frequently used to denote the Tridentine Mass, that is, the Roman - Rite liturgy of the Mass celebrated in Latin and in accordance with the successive editions of the Roman Missal published between 1570 and 1962 . </P> <P> In most countries, the Tridentine Mass was celebrated only in 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 . There "Tridentine Mass" was not synonymous with "Latin Mass". </P> <P> A further distancing between the concepts of "Tridentine Mass" and "Latin Mass" was brought about by the 1964 Instruction on implementing the Constitution on Sacred Liturgy of the Second Vatican Council, which 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 . Permissions were thus granted from 1967 onwards to celebrate most of the Tridentine Mass in vernacular languages, including the Canon . </P>

When did the latin mass change to english