When was Malchus Koresh?
Rashi: He ruled after Daryavesh ha'Midi, who ruled only one year, and he was killed in war, like it says in Sefer Yosef ben Guryon. Amidst the army, they made Koresh, his son-in-law, the next king.
Did Daniel live also after Malchus Koresh?
Ibn Ezra: Here shows that he did not live longer, for he was old 1 . There are two proofs that Sheshbatzar (in Ezra 1:8) is Zerubavel, and not Daniel 2 . (a) Zerubavel was Pachas Yehudah (Chagai 2:21); Sheshbatzar was called "Di Pechah" (Ezra 5:14). (b) Zecharyah said (4:9) "Yedei Zerubavel Yasdu ha'Bayis ha'Zeh", and it says in Ezra (5:16) "Edayin Sheshbatzar Dech Asa Yehav Ushya Di Veis Elaka."
Malbim: Above (1:21), it says that he lived until the first year of Koresh. Mahari explains based on Yosifun, that after he was thrown to the lions' den, he requested exemption from his work and to go to Shushan; this was granted. Zerubavel entered the palace in his place. Daryavesh died and Koresh ruled in place of him. Daniel remained there until Bnei Golah ascended to Yerushalayim.
