One of the Vatican's leading Latin experts, Bacci strongly opposed the introduction of the vernacular into the Mass.[3] In what was known as the Ottaviani Intervention, the 84-year-old Bacci, together with 79-year-old Alfredo Ottaviani, sent to Pope Paul VI, with a short covering letter from themselves, a study by a group of theologians under the direction of Archbishop Marcel Lefebvre criticizing the draft Order of Mass of the revision of the Roman Missal.[4] In their letter the two cardinals said that the study showed that the new Order of Mass "represents, both as a whole and in its details, a striking departure from the Catholic theology of the Mass as it was formulated in Session 22 of the Council of Trent ... to which, nonetheless, the Catholic conscience is bound forever. With the promulgation of the Novus Ordo, the loyal Catholic is thus faced with a most tragic alternative."
Among Bacci's publications was Lexicon Eorum Vocabulorum Quae Difficilius Latine Redduntur, a dictionary of modern terms in Latin; he invented such words as gummis salivaria ("chewing gum"), barbara saltatio ("the twist"), and diurnarius scriptor ("newspaper reporter").[3][5] This was a standard reference for writers of Modern Latin, especially at the Vatican, until it was superseded by the Lexicon Recentis Latinitatis.
Bacci died at Vatican City, at age 85. He is buried in his native Giugnola, near Florence.
^"Archbishop Lefebvre gathered together a group of 12 theologians who wrote under his direction, A Short Critical Study of the Novus Ordo Missae often called the Ottaviani Intervention." A Short History of the SSPXArchived 24 September 2015 at the Wayback Machine