The great historian of the Roman Rite and towering leader of the liturgical movement, Rev. Josef A. Jungmann, S.J., whose Mass of the Roman Rite is considered a foundational text, reports on his experience of attending the opening of the Second Vatican Council as a peritus, or expert:
The opening was not a pleasant affair for me. Still without an identity card, I had to make my way into the Vatican with my decree of appointment but without instructions on place and time. Wherever I asked, the only answer was: “Not this way!” Finally, after an hour of vainly walking around, I reached the basilica and there was courteously led by an assignator to the places reserved for the experts, but almost none of these was to be found there (wrong side of the galleries). At any rate, from there I had a good view of the bishops’ entrance and could hear everything very clearly. As a liturgical action indeed it was carried out correctly; good church music, excellent acoustic equipment, but the whole conception was in the style of Leo XIII. They learned nothing from the statio orbis in Munich. A high Mass without distribution of communion. Instead of integrating the opening actions (gospel in several languages, address of the Pope, profession of faith, intercessions…) all these gave way to the impression of being an appendage without any order. A flectamus genua followed by the litany! The ugly prayer, Adsumus, to the Holy Spirit (as I was able to tell Bugnini, it comes from Pseudo-Isidore) at least was not recited by all but by an individual. But most people there were pleased by it. Perhaps the idea was to make clear the terminus a quo in matters liturgical!
From Alberigo and Komonchak, The History of Vatican II, Volume II.