Daniel 1:21

And Daniel continued even unto the first year of king Cyrus -When the proclamation was issued by him to rebuild the temple at Jerusalem,Ezra 1:1. That is, he continued in influence and authority at different times during that period, and, of course, during the whole of the seventy years captivity. It is not necessarily implied that he did not “live” longer, or even that he ceased then to have influence and authority at court, but the object of the writer is to show that, during that long and eventful period, he occupied a station of influence until the captivity was accomplished, and the royal order was issued for rebuilding the temple.