Jerome makes a common-language Bible

In the decades after Melito wrote back to Onesimus with his list of canonical books, other Christians also published lists of the Old Testament books (notably Origin, Athanasius, and Tertullian of Carthage), and the only serious question was whether the Apocryphal books should be included.  All the church Fathers included them until Jerome, who lived from 346-420 A.D.

By his day, the Roman Empire had become permanently divided into eastern and western political halves, and the two parts had grown apart culturally as well.  Whereas in St. Paul's day educated people spoke both Latin and Greek easily, by Jerome's time citizens of the western empire spoke only Latin, and citizens of the eastern empire spoke only Greek.  Jerome, however, received an excellent education and was unusual for speaking and reading not only his native Latin but also Greek.  And in his early career he lived in Antioch for some time, where he learned to read Hebrew and Aramaic as well.

From Antioch he returned to Rome, where in about 382 A.D. Pope Damasus asked him to revise the Latin Bible.  Western (or Latin) Christians could only read the Bible in Latin, and all the available Latin translations were very poorly done.  He decided on a novel approach: rather than translating from the LXX, he decided to return to Palestine and there translate directly from the Hebrew and Aramaic sources into Latin.  He finished his work about 405 AD.