וַיָּשֶׂם֩ הַמֶּ֨לֶךְ אחשרש [אֲחַשְׁוֵר֧וֹשׁ ׀] מַ֛ס עַל־הָאָ֖רֶץ וְאִיֵּ֥י הַיָּֽם׃
און דער מלך אַחַשוֵרוֹש האָט אַרױפֿגעלײגט אַ צינז אױפֿן לאַנד, און אױף די אינדזלען פֿון אים.
Ibn Ezra
King Ahasuerus imposed tribute on the land. [Areas] that were not under his kingship, but feared him, and also on islands distant from him. And the verse mentions this to inform that he succeeded in all of his ways, and his strength was seen, now that Mordekhai was his deputy.