7 Heb “Shushan” (so , ). Most recent English versions render this as “Susa.” The city of Susa served as one of several capitals of Persia during this time; the other locations were Ecbatana, Babylon, and Persepolis. Partly due to the extreme heat of its summers, Susa was a place where Persian kings stayed mainly in the winter months. Strabo indicates that reptiles attempting to cross roads at midday died from the extreme heat (Geography 15.3.10–11).
8 The Hebrew word בִּירָה (birah) can refer to a castle or palace or temple. Here it seems to have in mind that fortified part of the city that might be called an acropolis or citadel. Cf. “palace”; “stronghold”; “capital”; “fortress.”

In other versions

in those days when King Ahasuerus sat on his royal throne in Susa, the citadel,

At that time King Xerxes reigned from his royal throne in the citadel of Susa,

In those days King Ahasuerus reigned from his royal throne in the fortress at Susa.

At that time Xerxes ruled his empire from his royal throne at the fortress of Susa.

In those days as King Ahasuerus was sitting on the throne of his kingdom, which was in the citadel of Susa,

That in those days, when the king Ahasuerus sat on the throne of his kingdom, which was in Shushan the palace,

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