Book of Deuteronomy have given various answers to the problem. The Deuteronomistic history theory is currently the most popular (Deuteronomy was originally just the law code and covenant, written to cement the religious reforms of Josiah, and later expanded to stand as the introduction to the full history); but there is an older theory which sees Deuteronomy as belonging to Numbers, and Joshua as a sort of supplement to it. This idea still has supporters, but the mainstream understanding is that Deuteronomy, after becoming the introduction to the history, was later detached from it and included with Genesis-Exodus-Leviticus-Numbers because it already had Moses
Development of the Old Testament canon "Apocrypha" ("hidden"). To counter Luther's "heresy", the fourth session of the Catholic Council of Trent in 1546 confirmed that the deuterocanonical books were equally authoritative as the protocanonical in the Canon of Trent in the year Luther died. Following Jerome's "Veritas Hebraica" (truth of the Hebrew) principle, the Protestant Old Testament consists of the same books as the Hebrew Bible, but the order and division of the books are different. Protestants number the Old Testament books at 39, while the Hebrew Bible numbers the same books as 24. The Hebrew Bible counts Samuel, Kings, and Chronicles as one book each,