My father often points out that the Catholic church says that the Muslims worship the same God as the Christians (CCC 841). He believes that they actually worship a moon god.
In researching this I have found that Nostra Aetate 3 references “St. Gregory VII, letter XXI to Anzir (Nacir), King of Mauritania (Pl. 148, col. 450f.)” Where would I find this document? I want to show my father that the church’s understanding of the God the Muslims worship dates to time that is much closer to the founding of Islam than Vatican II.