The Theotokos, Model of Faith: Affirming The Primacy of Christ and the Cooperative Role of Mary The Dicastery for the Doctrine of the Faith’s Doctrinal Note, Mater Populi fidelis (Mother of the Faithful People) , serves as a crucial clarification regarding Marian titles and her cooperative role in the work of salvation, which must always be Christocentric. Accordingly, the document Mater Populi fidelis firmly grounds Mary’s singular position not as an object of devotion plac