The Additions to Esther
The Septuagint appears to be a free translation of the Masoretic Text (MT) or a Hebrew text close to the MT, with six additions (labeled A-F). These additions include Mordecai’s dream (A) and its explanation of fulfillment (F); the texts of two edicts issued by Artaxerxes, Hebrew Xerxes (B and E); and the prayers of Mordecai and Esther (C), which add a clear theological element lacking in the MT. Additions A, C, D, and F likely originated in a Semitic language, though a more precise identification cannot be agreed upon, while the two royal edicts (B and E) were originally composed in Greek. The final verse of additions F, often referred to as the colophon, claims that LXX Esther was translated in Jerusalem no later than 114 BCE, at which point it was brought to Egypt. However, the additions may have been placed in the work after this postscript and the actual dating of provenance of Greek Esther continues to be debated. There are inconsistencies, such as the name of the king, and contradictions to the MT throughout Greek Esther, such as the dating of Mordecai’s discovery of the plot against the king, which marks them clearly as later additions.
For more information, look at Jon D. Levenson, Esther, OTL (Louisville: Westminster, 1997), especially in his introduction. Bonus: this volume came highly recommended by Jo Ann!