Biblical canon
The translation was prepared with a definite polemical purpose in opposition to Protestant translations (which also had polemical motives). Prior to the Douay-Rheims, the only printed English language Bibles available had been Protestant translations. The Tridentine–Florentine Biblical canon was naturally used, with the Deuterocanonical books incorporated into the Douay–Rheims Old Testament, and only 3 Esdras, 4 Esdras and the Prayer of Manasses in the Apocrypha section.