The surviving repertoire of liturgical music of the California missions presents a challenge to modern interpretation. The nature of the surviving manuscripts-their fragmentary state, the archaic notation, and non-standard notational conventions-causes a great deal of misunderstanding and mischaracterization of the music, confounding both editors and prospective performer. A dearth of scholarship dealing with the performance practice of this repertoire has resulted in a general lack of historically-informed performing editions and the stifling of this repertoire's revival. This study examines five areas that are particularly opaque to modern musicians: notation, genre, authorship, choral voicing, and orchestration, and proposes a new paradigm for the performance of this repertoire.