Source texts - Old Testament

The Masoretic Text is the authoritative Hebrew and Aramaic text of the 24 books of the Tanakh in Rabbinic Judaism. It was primarily copied, edited and distributed by a group of Jews known as the Masoretes between the 7th and 10th centuries AD.
It is used as the basis for most Protestant translations of the Old Testament. The Hebrew text that has served as the basis for most translations of the OT into English is based almost entirely on the Leningrad Codex, which dates from 1008 AD.

Although the Septuagint is a Greek translation from the Hebrew it was composed up to 4 centuries before the first Masoretic (300 BC compared to 100 AD) and the oldest complete copy (4th century AD) is 6 centuries earlier than the oldest Masoretic complete copy.

The Aleppo Codex (c. 920 AD) and Leningrad Codex (c. 1008 AD) – part of the Masoretic tradition- were once the oldest known manuscripts of the Tanakh in Hebrew. In 1947 AD the finding of the Dead Sea scrolls at Qumran pushed the manuscript history of the Tanakh back a millennium from such codices.