Rashi on Esther
1 א

וַיְהִי בִּימֵי אֲחַשְׁוֵרוֹשׁ. מֶלֶךְ פָּרַס הָיָה, שֶׁמָּלַךְ תַּחַת כּוֹרֶשׁ לְסוֹף שִׁבְעִים שָׁנָה שֶׁל גָּלוּת בָּבֶל:

It was in the days of Achashveirosh. He was the king of Persia1The Persians conquered the Babylonians, and Achashveirosh succeeded Koresh to the Persian throne in the year 3392. who reigned in place of Koresh2There were other Persian kings with the name “Achashveirosh,” therefore Rashi identifies which “Achashveirosh” he was. (Mizrachi) at the end of the seventy years of the Babylonian exile.

2 ב

הוּא אֲחַשְׁוֵרוֹשׁ. הוּא בְרִשְׁעוֹ מִתְּחִלָּתוֹ וְעַד סוֹפוֹ:

He was [the] Achashveirosh. He was equally wicked from beginning to end.3Maseches Megillah 11a. He did not allow the resumption of the building of the Bais Hamikdosh after it had been suspended.

3 ג

הַמֹּלֵךְ. שֶׁמָּלַךְ מֵעַצְמוֹ וְלֹא הָיָה מִזֶּרַע הַמְּלוּכָה:

Who reigned. He reigned on his own, and was not of royal seed.4Ibid. He was very wealthy and he acquired the throne by distributing his money.

4 ד

מֵהֹדּוּ וְעַד כּוּשׁ, וגו'. הַמּוֹלֵךְ עַל מֵאָה וְעֶשְׂרִים וְשֶׁבַע מְדִינוֹת כְּמוֹ שֶׁמָּלַךְ מֵהֹדוּ וְעַד כּוּשׁ שֶׁעוֹמְדִים זֶה אֵצֶל זֶה. וְכֵן "כִּי הוּא רֹדֶה בְּכָל עֵבֶר הַנָּהָר מִתִּפְסַח וְעַד עַזָּה", שֶׁהָיָה רוֹדֶה בְּכָל עֵבֶר הַנָּהָר כְּמוֹ שֶׁהוּא רוֹדֶה מִתִּפְסַח עַד עַזָּה:

From Hodu to Cush, etc. Who reigned over one hundred and twenty-seven provinces [with the same authority] as he reigned from Hodu5India. to Cush,6Ethiopia. which are situated alongside one another,7Maseches Megillah 11a. and similarly [we explain], “For he ruled over the entire area beyond the [Euphrates] river, from Tiphsach to Gaza,”8I Melochim 5:4. [meaning] that he ruled over this side of the river, [with the same authority] just as he ruled over Tiphsach to Gaza.8Otherwise why mention only these two provinces.