Esther 1:10 (ESV)

10 On the seventh day, when the heart of the king was merry with wine, he commanded Mehuman, Biztha, Harbona, Bigtha and Abagtha, Zethar and Carkas, the seven eunuchs who served in the presence of King Ahasuerus,

It is easy to imagine that by the seventh day of the feast, Ahasuerus and his companions would be engaged in drunken boasts concerning their wives and mistresses. Ahasuerus had already showed them his wealth, but they had not yet seen his greatest pride: his beautiful queen.

Thus, he sent his seven eunuchs to go and fetch Vashti. (Eunuchs were castrated men who had many responsibilities in the palace. Among other things, they had to guard the harem.)

The author gives the name of each eunuch, each name being typically Persian. This shows how well informed the author was of events at the Persian court.