Pope Damasus I first commissioned Jerome to revise the existing Old Latin gospels against the Greek text, a relatively cautious task Jerome completed while still in Rome. What followed in Bethlehem was far more ambitious and, in its own time, controversial: rather than revising the Old Latin Old Testament against the Greek Septuagint, the text nearly all earlier Christian translators had used, Jerome chose to translate directly from the Hebrew, a method he called hebraica veritas, the Hebrew truth, on the grounds that a translation should work from the language a text was actually composed in.
The choice drew real opposition. Augustine of Hippo, corresponding with Jerome across a tense and only partly resolved exchange of letters, worried that abandoning the Septuagint, which tradition already held to be divinely inspired and which underlay every existing Latin lectionary, would fracture the unity of the church's scripture and cause needless scandal among congregations used to the older wording. Jerome held his ground, though the disagreement, covering translation method, the interpretation of Galatians, and matters of scholarly courtesy, was never fully settled between them.
Jerome's translation, later known as the Vulgate, from the Latin for commonly used, did not become the church's standard Bible in his own lifetime; it competed with Old Latin versions for centuries before the Council of Trent formally declared it authoritative in 1546. His method also shaped the Old Testament canon itself, since Jerome distinguished the Hebrew scriptures from a set of Greek-only books, later called the Apocrypha in Protestant usage and the deuterocanon in Catholic usage, a distinction that outlived him by more than a thousand years.