Mordecai resided in Susa, the metropolis of Persia.
He adopted his cousin
Hadassah (
Esther), an orphan child, whom he tenderly brought up as his own daughter. When she was brought into the harem of king Ahasuerus and made queen in the place of the deposed queen
Vashti,
Mordecai was promoted to some office in the court, and was one of those who "sat in the king's gate". While holding this office, he discovered a plot of the eunuchs to put the king to death, which, by his vigilance, was defeated. His services to the king in this matter were duly recorded in the royal chronicles.
Haman the Agagite had been raised to the highest position at court.
Mordecai refused to bow down before him; and Haman, being stung to the quick by the conduct of
Mordecai, resolved to accomplish his death in a wholesale destruction of the Jewish exiles throughout the Persian empire. Tidings of this cruel scheme soon reached the ears of
Mordecai, who communicated with
Queen Esther regarding it, and by her wise and bold intervention the scheme was frustrated. The Jews were delivered from destruction,
Mordecai was raised to a high rank, and Haman was executed on the gallows he had by anticipation erected for
Mordecai. In memory of the deliverance thus wrought for them, the Jews to this day celebrate the feast of Purim.
(from Wikipedia)