At this period of time we think Esther and Judith lived, but I confess that I cannot easily perceive with what kings especially I should connect the actions of their lives. For, while Esther is said to have lived under King Artaxerxes, I find that there were two Persian kings of that name, and there is much hesitation in concluding to which of these her date is to be assigned. However, it has seemed preferable to me to connect the history of Esther with that Artaxerxes under whom Jerusalem was restored, because it is not likely that, if she had lived under the former Artaxerxes, whose times Esdras has given an account of, he would have made no mention of such an illustrious woman.
This is all the more convincing since we know that the building of the temple was (as we have related above) prohibited by that Artaxerxes and Esther would not have allowed that had she then been united with him in marriage. But I will now repeat what things she accomplished. There was at that time a certain Vastis connected with the king in marriage, a woman of marvelous beauty. Being accustomed to extol her loveliness to all, he one day, when he was giving a public entertainment, ordered the queen to attend for the purpose of exhibiting her beauty.
But she, more prudent than the foolish king, and being too modest to make a show of her person before the eyes of men, refused compliance with his orders. His savage mind was enraged by this insult, and he drove her forth, both from her condition of marriage with him and from the palace. Consequently, when a young woman was sought after to take her place as the wife of the king, Esther was found to excel all others in beauty. She being a Jewess of the tribe of Benjamin, and an orphan, without father or mother, had been brought up by her cousin-german, Mardochæus.
On being espoused to the king, she, by the instructions of him who had brought her up, concealed her nation and fatherland, and was also admonished by him not to become forgetful of her ancestral traditions, nor, though as a captive she had entered into marriage with a foreigner, to take part in the food of the heathen. Thus, then, being united to the king, she, in a short time, as was to be expected, easily captivated his whole mind by the power of her beauty, so that, equalizing her with himself in the emblem of sovereign power, he presented her with a purple robe.
Source: Sacred History (New Advent)