In the first month, that is the month Nisan
Which was the first month of the sacred year of the Jews, by divine appointment, ( Exodus 12:2 ) ( 13:4 ) , and there called Abib, and answers to part of February and part of March; from hence it is clear this book was written by a Jew, and very probably by Mordecai:
in the twelfth year of King Ahasuerus;
four years and near two months after his marriage of Esther, ( Esther 2:16 ) ,
they cast Pur, that is, the lot, before Haman;
being a Persian word, it is explained in Hebrew a lot, the word signifying "steel" in the Persian language. Reland F16 conjectures that this was that sort of lot called "sideromantia". Who cast this lot is not said; whether Haman himself, or one of his servants: perhaps a diviner. The latter Targum calls him Shimshai the scribe:
from day today, and from month to month, to the twelfth month, that is
the month Adar;
which answers to part of January and part of February; so that the lot was cast for every month and every day of the month throughout the year, to find out which was the most lucky month, and which the most lucky day in that month, to destroy the Jews in and none could be found till they came to the last month, and the thirteenth day of that month, ( Esther 3:13 ) , the providence of God so overruling the lot, that there might be time enough for the Jews, through the mediation of Esther to the king, to prevent their destruction; so in other nations the Heathens had their lucky and unlucky days F17.
The Brenton translation of the Septuagint is in the public domain.