This coming Friday, December 13th, we will observe the Tenth of Tebet, a fast day which remind us of three tragic events. The main event we recall on this day is the onset of the siege of Jerusalem by Nebuḥadnezzar, the King of Babylonia. But there were other two events that we also remember in this day, the rendition of the Tora into the Greek language and the death of Ezra haSofer.
On the 8th of Tebet (=today), approximately in the year 300 BCE, in Alexandria, Egypt, King Ptolemy ordered 72 Jewish scholars to translate the Tora (the five Books of Moshe or Pentateuch) to Greek. King Ptolemy sought to disprove the existence of an unified Jewish tradition to find an excuse to humiliate the Jews. The 70 scholars were placed in separate workrooms. Yet, they all translated the Tora in the same exact way.
This translation of the Tora is known as the Septuagint. Although it was done by prominent Rabbis, the Septuagint is not considered a translation which follows necessarily rabbinical tradition. As explained in Talmud Yerushalmi (Megila 9) in many cases the authors of the Septuagint deliberately deviated from the traditional Jewish understanding of the Tora and adapted the Biblical text to the Greek mentality and sensitivities to please the king and avoid a situation of danger for the Jews
As a whole, translating the Tora to Greek was considered a dark event by Jewish historiography. Why? Because the new Greek Bible was used to advanced the agenda of the Hellenist Jews who sought to syncretize Greek and Jewish values. Eventually the Septuagint paved the way for the advancement of non-Jewish "Biblical" religions. Unlike pagan cults which were clearly antagonistic to the Tora, these new religions were now supposedly based on the Jewish Scripture. The Bible was now reinterpreted and used to justify non-Jewish ideas or beliefs "in the name of the Bible", all of which caused uncountable tragedies to the Jewish people.
As Timothy McLay explains, "the Jewish Scriptures as they were known, read and interpreted in the Greek language, provided the basis for much, if not most, of the interpretive context of the New Testament."
BTW, the official Jewish translation of the Tora is the Targum Onqelos (aka Targum Didan) done ca. 100 CE.