This edition is based on two sources, namely Librone 1, ff. 147v–149r (copied by Scribe A) and Librone 3, ff. 128v–130r (copied by Scribe I). Librone 1 omits the last part of the motet (after ‘Libera nos, o Maria’).
The scribes mostly used a standard orthography, but introduced quite a few semantic variants. In the first verse Scribe A wrote ‘virgo’ instead of virga in C and T1: this variant, however, makes little sense in the context. Also, he wrote ‘puerperi’ instead of puerperio in C and T2 (the missing final letter was probably forgotten after the turn of the page). In Librone 3 Scribe I wrote ‘reatu’ instead of peccatis in B, but in this case the variant is not problematic grammatically and can be considered equivalent to the prevailing reading peccatis.
The motet draws mostly on Marian sequences – inter alia, the sequence Verbum bonum et suave (AH 54, no. 218, pp. 343–45, verse 5), from which the first verse is taken – but also includes a verse taken from a Marian prayer (‘Gaude virgo fruens deliciis, / Expurga nos a nostris vitiis, / Iam rosa iuncta lilio, / Et iunge tuo filio’).^[1] The text recalls the structure (‘Gaude… Gaude… Gaude...’) of poems about the ‘Joys of Mary’, a theme widespread in late medieval piety. In general the motet alternates salutations of Mary (‘Ave’, ‘Gaude’) with requests for intercession and help for sinners (‘Libera nos’, ‘Expurga nos’, ‘Exaudi nos’).

^[1] The idea of a possible Premonstratensian origin of this verse is raised in François Petit, O. Praem., La spiritualité des prémontrés au XII^e et XIII^e siècles (Paris: Vrin, 1947).