The Septuagint is the Greek translation of the Hebrew Scriptures (Old Testament). Initially, the Septuagint was made by Jews for the Jewish community, and they felt that it was just as inspired as the Hebrew Scriptures. However, it was used heavily by the early Church in their evangelism, pricing that Jesus was the long-awaited Messiah, which caused the Jews to return to the Hebrew.
The Old Testament, the inspired Word of God, how was it copied, maintained as to the textual reliability, and handed down throughout the past three thousand years? It should be appreciated that what we possess today is nothing short of the Word of God that the Old Testament writers penned throughout a 1,600-year period, from the time of Moses to Malachi.