Esther 3:3-7

Then the king’s servants who were at the king’s gate said to Mordecai, “Why are you disregarding the king’s command?” Now it happened when they had spoken to him day after day and he would not listen to them, that they told Haman to see whether Mordecai’s reason [for his behavior] would stand [as valid]; for he had told them that he was a Jew. When Haman saw that Mordecai neither bowed down nor paid homage to him, he was furious. But he disdained laying hands on Mordecai alone, for they had told him who the people of Mordecai were (his nationality); so Haman determined to destroy all the Jews, the people of Mordecai, who lived throughout the kingdom of Ahasuerus. In the first month, the month of Nisan (Mar-Apr), in the twelfth year of King Ahasuerus, Haman cast Pur, that is, the lot, cast before him day after day [to find a lucky day to approach the king], month after month, until the twelfth month, the month of Adar (Feb-Mar).