Why is the ninth month called September?
c.1600, Latin translation of the Bible, especially that completed in 405 by St. Jerome (c.340-420), from Medieval Latin Vulgata, from Late Latin vulgata "common, general, ordinary, popular" (in vulgata editio "popular edition"), from Latin vulgata, fem. past participle of vulgare "make common or public," from vulgus "the common people" (see vulgar). So called because the translations made the book accessible to the common people of ancient Rome.
(from the Latin editio vulgata: "common version"), Latin Bible used by the Roman Catholic Church, primarily translated by St. Jerome. In 382 Pope Damasus commissioned Jerome, the leading biblical scholar of his day, to produce an acceptable Latin version of the Bible from the various translations then being used. His revised Latin translation of the Gospels appeared about 383. Using the Septuagint Greek version of the Old Testament, he produced new Latin translations of the Psalms (the so-called Gallican Psalter), the Book of Job, and some other books. Later, he decided that the Septuagint was unsatisfactory and began translating the entire Old Testament from the original Hebrew versions, a process that he completed about 405.