1)
Who was "Malkesa"?
1.
Ibn Ezra: Some say that this was Nebuchadnetzar's wife. Malbim - she was Belshatzar's mother or grandmother 1 .
2.
Malbim: Some say that even though the other wives were at the party, the special queen stayed in her palace.
2)
Why did the queen come?
1.
Rashi: She heard the words of the king and officers.
2.
Malbim: She wanted to remove his great fear.


