In the days of Esther, when the Jews were allowed to stand for their lives, that was in an empire of huge size. What do you think was meant by the word - Jews? This would have been around 100 years or so after the Jews returned under the decree of Cyrus. History has a question as to the actual date and what king is meant in Esther. But it seems that we can't go too far out, because Esther 2:5-6 tells that Mordecai -seems had a relative - a Benjamite - "had been carried away from Jerusalem...of Babylon carried away."