Esther 1:2

1:2 In those days, as King Ahasuerus sat on his royal throne in Susa ¹  the citadel, ² 

Esther 7:10

7:10 So they hanged Haman on the very gallows that he had prepared for Mordecai. The king’s rage then abated.

¹ tn Heb “Shushan” (so KJV, ASV). Most recent English versions render this as “Susa.”

² tn 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. KJV “palace”; NAB “stronghold”; NASB “capital”; NLT “fortress.”