The above clip is the offertory of Fr. Sean Finnegan's 1997 celebration of Candlemas according to the Sarum use in Merton College Chapel, a variation of the Roman rite unique to the city of Salisbury and which English clergy widely celebrated until the reign of Henry VIII.
Here we see many variations of the very simple Roman Mass that I cannot help but think improve, but not over-ornament, the quality of the celebration. First one will note that the offertory prayers are startling short compared to the Roman missal's. This is because the host and chalice are offered in one prayer, as is the case in many monastic and local rites still celebrated in the right places to this day, but also because the chalice has already been prepared. The medieval Latin rite had both a flair for liturgical drama and a singular focus on the sacrificial nature of the Mass. A spirit of anticipation led many local and monastic clergy to prepare the chalice with water and wine during the gradual (at high Mass) or before the prayers at the foot of the altar (low Mass). One contribution of this feature is that the Mass becomes a complete, unified action, one visible to those gathered.
Near the camera we see "rulers of choir," something allowed but extinct in the Roman rite outside of Lauds and Vespers. There are three here, but there would have been an even number, with equal numbers on each side of the lectern. These men, who I imagine during older times were priests, "ruled" the choir by intoning various chants or by acting as cantors during the propers of the Mass. The wearing of vestments accentuates the role of the musician as a liturgical actor.
One sees three people wearing diaconal vestments rather than two. The acolyte was not the candle-guy in the Sarum rite. He was a minister of the Mass, just below the subdeacon in rank. The subdeacon held and sang texts and assisted the priest at the altar in these northern European rites. The acolyte, who in the Middle Ages would be apprenticing for the priesthood (remember, no seminaries until Trent), handled sacred vessels and held the paten under the veil during the Canon of the Mass. There is no strong delineation between "major" and "minor" orders in this sort of liturgy as there was in the Roman rite after Trent. I sense the subdeacon absorbed the duties of the acolyte in the Roman rite, giving us the practice of the subdeacon holding the paten today. Vatican II decided the subdeacon was not a major minister after all and Paul VI, in 1972, abolished the order of subdeacon altogether. Eastern Catholic and Eastern Orthodox Churches never held the subdeacon to be a member of major orders, which is why laymen may "vest" as subdeacon during pontifical Divine Liturgies.
Those incensed kiss a book of the Gospels (the Sarum missal just says the "text"). I will go out on the proverbially edge and guess that this is an influence from pontifical Mass which has insinuated the regular sacerdotal Mass. No problem with that. If this was somehow a corruption then we ought to remove the Gloria from non-Papal Masses.
Lastly, I would like to offer a few remarks on the motet of the offertory, John Sheppard's Gaude, Gaude, Gaude Maria Virgo, to my mind one of the most under-appreciated polyphonic pieces ever composed. I generally favor chant over polyphony. I find chant more "charismatic" (I mean that in a traditional sense) and I find most polyphony absolutely flat and vapid. Good polyphony reflects our journey to heaven, slowly starting on the ground and gradually rising up to heaven, with a few drops along the way. Once above, it becomes sublime. This piece does that. Its arrangement does not eschew plainsong either, permitting a line of chant betwixt each verse, before starting again at the bottom and rising upward.
Sadly, this was the last celebration of the Sarum use in Oxford. Oddly, Archbishop Conti celebrated the Sarum Mass in Aberdeen, Scotland (where it was never said before the Reformation) in 2000. There have been no Catholic celebrations of it since. I have heard rumors that the Russian Orthodox Church has installed an altered version as part of their Western Orthodoxy program, but I cannot comment on this practice, as I am unfamiliar with it.
The end of these Sarum celebrations is an awkward story. Apparently someone denounced the celebrations to the Archbishop of Birmingham—who did not care, as he had approved the Mass before hand—then to Cardinal Hume of Westminster. Unable to get any traction, this fellow wrote to Rome. Fr. Jerome Bertram, a fellow Oratorian with Fr. Finnegan and the preacher of the sermon for the celebration above, recounts that Rome assumed the Oxford group formed to organize this Mass, the "St. Osmund Society," was a British version of the "Society of St. Pius X" and immediately asked for the Masses to desist. Fr. Bertram recounts that the short-lived group is remembered by its former members as the "Donny Osmund Society."