Esther was the heroine and central figure in the Biblical book of Esther. She was crowned about 55 years after the destruction of the First Temple, and fifteen years before the Second Temple was built. The Jews were in the Babylonian exile. A few of them, such as Nehemiah, Mordecai and Daniel, rose to positions of prominence under the Babylonian kings.
The last of the Prophets of the Tanakh (Hebrew Bible) were still living.
King Cyrus had recently made his famous proclamation (2 Chronicles 36:22-23) allowing the Jews to resettle Judea (Israel), and some had gone up with Zerubavel, but the enemies of the Jews had then slandered them (Ezra ch.4), causing the Babylonian king to put a stop to the rebuilding and resettlement of Judea. This last event was around the same time that Esther became Queen.