The Masoretic Text is widely used as the basis for translations of the Old Testament in Protestant Bibles, and in recent years (since 1943), for some versions of Catholic Bibles in terms of translation, but not of canon. The Catholic Church and Eastern Orthodox churches continue to use the canon used by the Hellenistic Jews and Jesus of Nazareth and which is referenced in the New Testament, called the Septuagint, holding it to be divinely inspired, and Roman Catholics have, as their official version of Scripture, the version translated, by St. Jerome, into Latin, called the "Vulgate," based on the Septuagint's canon. In modern times the Dead Sea Scrolls have shown the Masoretic Text to be nearly identical to some texts of the Tanakh dating from 200 BCE but different from others. The 2000-year-old En-Gedi Scroll, found in 1970 but which had not had its content reconstructed until recently, found that the Book of Leviticus text in the En-Gedi scroll is 100% identical to the Hebrew text of the Book of Leviticus in the Masoretic Text. The En-Gedi scroll is the first time a biblical scroll has been discovered in an ancient synagogue's holy ark, where it would have been stored for prayers, and not in desert caves like the Dead Sea Scrolls.
The Masoretic Text was primarily copied, edited and distributed by a group of Jews known as the Masoretes between the 7th and 10th centuries CE. Though the consonants differ little from the text generally accepted in the early 2nd century (and also differ little from some Qumran texts that are even older), it has numerous differences of both greater and lesser significance when compared to the manuscripts of the Septuagint, a Greek translation (about 1000 years older than the MT made in the 3rd to 2nd centuries BCE) of the Hebrew Scriptures that was in popular use in Egypt and Israel (and was used in the quotations in the New Testament, especially by Paul the Apostle).
The Hebrew word mesorah (מסורה, alt. מסורת) refers to the transmission of a tradition. In a very broad sense it can refer to the entire chain of Jewish tradition (see Oral law). This Jewish tradition is claimed (by Orthodox Judaism) to be unchanged and infallible. However when one looks at some of the discussions in the Talmud one can see that this tradition (mesorah) is not unchanged and infallible because the Talmud mentions different opinions and recollection of the law (Halacha). Moreover in reference to the Masoretic Text the word mesorah has a very specific meaning: the diacritic markings of the text of the Hebrew Bible and concise marginal notes in manuscripts (and later printings) of the Hebrew Bible which note textual details, usually about the precise spelling of words.
The oldest extant manuscripts of the Masoretic Text date from approximately the 9th century CE. The Aleppo Codex (once the oldest known complete copy of the Masoretic Text, but now missing its Torah section) dates from the 10th century.