After the Babylonian captivity, Aramaic replaced Biblical Hebrew as the everyday language in Israel.  However, Biblical Hebrew was still used for religious purposes.  After Alexander the Great, the Ptolemies and the Seleucids ruled Israel for almost two hundred years.  Thus, the Jewish culture was heavily influenced by this Hellenistic culture.  Koine Greek was used not only for international communication, but also as the first language of some Jews.  This development was furthered complicated by the fact that the largest Jewish community in the world lived in Ptolemaic Alexandria, Egypt.  Many of these diaspora Jews would have Greek as their first language.  Thus, first the Torah, and then other Hebrew scriptures, were translated into standard Koine Greek, the Septuagint.