Daniel 4:22

It is thou, O king, that art grown, and become strong
Here begins the interpretation of the dream: the tree was an emblem of King Nebuchadnezzar, of his greatness, and growing power and strength: for thy greatness is grown, and reacheth unto heaven;
he overtopped all the kings of the earth, exceeding them in honour and power, and aspired to deity itself; (See Gill on Daniel 4:11) and thy dominion to the end of the earth;
as far as Hercules's pillars, as Strabo ^F17 says he came. Grotius interprets it, as far as the Caspian and Euxine sea, and the Atlantic ocean.