Eusebius On Melito and Origen
The first list of Old Testament books compiled by a Christian source is recorded by the 4th century historian Eusebius. Eusebius describes the collection of a 2nd century bishop, Melito of Sardis. Melito's list, dated to circa 170, the result of a trip to the Holy Land (probably the famous library at Caesarea Maritima) to determine both the order and number of books in the Hebrew Bible, instead seems to follow the order of the books presented in the LXX, yet he doesn't list the book of Esther or the apocrypha (except for possibly the Book of Wisdom).
Eusebius also records a 22-book canon of Origen of Alexandria.
Read more about this topic: Development Of The Old Testament Canon