in those days: i.e. the days when these events took place. At other times he dwelt at Ecbatana, or elsewhere. Esther 1:1 mentions the ruler; Esther 1:2, the place; Esther 1:1, the time.
sat. took his seat, or came to.
Shushan. Now, the ruins of Susa, on the river Shapur, east of Persian Gulf.
palace. castle, or fortress. Compare Nehemiah 1:1.