The Greek translation of the Hebrew Old Testament started in the third century B.C. in Alexandria, Egypt.  The name Septuagint comes from the Greek word for “seventy”; hence the symbol LXX in roman numerals.

It refers to the seventy-two Jewish translators brought to Egypt by Ptolemy II Philadelphus (285–246 B.C.) to translate the Hebrew Bible for the non-Hebrew-speaking Jews.  The translation was completed around 100 B.C.

It differed from the Hebrew Bible in the arrangement of the books and included several books, later called deuterocanonical, which were not acknowledged as sacred by the Palestinian community.

By the first century, the LXX was the Bibles of Greek-speaking Jews, and so was the most frequently used version of the Old Testament in the early Church; this is evident from the New Testament and patristic sources. (8:36)