User talk:2600:1700:8CC0:B180:25ED:8FC3:5668:62D9

noun
(Tr: On Sacred Music) The 1955 Vatican encyclical of Pope Pius XII that elaborated on the famous November 22, 1903 Moto Proprio of Pius X (tr: on “his” [Pope Pius X] own initiative), Tra Le Sollecitudini (tr: among the concerns.) These instructions on sacred music became Catholic Canon Law until the Second Vatican Ecumenical Council created a new Constitution on the sacred liturgy, Sancrosanctum Concilium on December 4, 1963 and its clarifying instruction, Musicam Sacram on March 5, 1967. These new instructions on sacred music were inspired by the previous encyclicals but replaced them in certain key areas such as acceptable use of the vernacular in the Missa Novus Ordo (tr: new order of the mass) and an emphasis on active participation by the faithful.

https://www.vatican.va/content/pius-xii/en/encyclicals/documents/hf_p-xii_enc_25121955_musicae-sacrae.html