Denoted by the symbol LXX, and taking the name from the legend that this translation into Greek of the Hebrew OT was undertaken at Alexandria by seventy (or seventy-two) Jewish scholars in as many days. The work was done in the time of Ptolemy II Philadelphus (285–246 BCE), but there were repeated revisions and also further translations (of Aquila, Theodotion, and Lucian). The LXX is a valuable check on the accuracy of the official Masoretic Hebrew text, which has also undergone revisions. There are 2nd-cent. BCE MSS fragments of the LXX among the Dead Sea scrolls. The LXX became the Bible of the early Christians; it included some books not contained in the Hebrew (the Apocrypha) while other books (e.g. Jeremiah) were shorter than in the Hebrew.
Septuagint Online – Resources for the study of the Septuagint and old Greek translations of the Hebrew scriptures
New English Translation of the Septuagint – This electronic edition contains the masters of the second printing of A New English Translation of the Septuagint, as published by Oxford University Press in 2009, including corrections and emendations made in the second printing (2009) and corrections and emendations made in June 2014.
The Septuagint LXX: Greek and English by Sir Lancelot C.L. Brenton