O king.

Daniel 6:6
So the administrators and satraps went together to the king and said, "O King Darius, may you live forever!

Daniel 2:4
Then the astrologers answered the king in Aramaic, "O king, may you live forever! Tell your servants the dream, and we will give the interpretation."

Nehemiah 2:3
and replied to the king, "May the king live forever! Why should I not be sad when the city where my fathers are buried lies in ruins, and its gates have been destroyed by fire?"