Musicam Sacram, Instruction on Music in the Liturgy, published March 5, 1967, by the Sacred Congregation of Rites. If you want to know what we’re supposed to be singing at Mass, this document provides the foundation. —————- Now playing: Corydon Singers, Matthew Best & Thomas Trotter – Missa Choralis, S. 10 : III. Credo via FoxyTunes