In his letter on my liturgical opinions (November AD2000), Fr G.H. Duggan SM goes too far in claiming that "there was no substantial change" in the Roman Rite of the Mass between Pope St Gregory the Great (who died in 603) and the Missal of Pope St Pius V (1570).
St Gregory inherited over five centuries of liturgical development. He sought to reform the liturgy in Rome and he defined the final version of the Roman Canon (which previously seems to have taken various forms). But the ten following centuries saw many more changes to the Mass, particularly from Gallican sources.
There was a variety of different "uses" in dioceses, regions and religious orders. Medieval additions to the rite were included in the standard Roman Missal of 1570. It was only then that the Roman liturgy entered an era of substantial uniformity, that is, from Trent to the Missal of Pope Paul VI, 1970.
People who remember the last years of that era of uniformity may imagine that the Mass was like that from the earliest centuries, hence the source of the myth.
Dom Alcuin Reid did not explode "the myth of an unchanging Mass of all ages". The process of gradual change explodes the myth, as I stated in my review of his excellent book, The Organic Development of the Liturgy. Any historian of the Roman Rite accepts the fact that a complex process of gradual change took place. What is under discussion today is the nature of this change.
Fr Duggan also sought a clarification. The Indult of Pope John Paul II for the celebration of the pre-conciliar rite specifies the use of the last edition of the Tridentine Missal, authorised by Blessed Pope John XXIII in 1962.
MSGR PETER J. ELLIOTT
East Malven, Vic