The service books of the Ambrosian rite were produced relatively late: the oldest copy of the Manuale, the first to record the texts and some rubrics, dates from the early eleventh century; the earliest redaction of the ordinal, from shortly after 1126; the oldest copy of the antiphoner, which contains the notated melodies of both Mass and Office, from the mid-twelfth. All these books document a liturgy that had been extensively revised after the Frankish conquest of northern Italy in 774. The Frankish reforms did not result in the suppression of the Milanese rite (as they had the Gallican), but many changes were effected, changes that brought the ancient liturgy of northern Italy – without destroying all of its indigenous features – closer to the new, international, Gregorian rite. The purpose of this article is to re-examine the earliest references to the Mass of pre-Conquest Milan and its archdiocese, which reveal more than has been suspected, and to present new evidence concerning the Ambrosian sacrifice as it was in the earliest centuries, even before the time of St Ambrose.
Terence Bailey has taught at three Canadian universities beginning in 1963. He has devoted most of his research since 1980 to the music and liturgy of the Milanese Church, and lately to the question of the relationship between Ambrosian and Gregorian chant repertoires.