Babylon with Nebuchadnezzar as its King was given through Daniel, Hananiah, Mishael, and Azariah a choice to make. The book of Daniel seems to show that as for Nebuchadnezzar he made a choice for God. But as for his descendants they did not make their choice for God but against Him.
The results of their decision can be noted in the way that Belshazzar lived out his choices. The problem is just this.once a country choose to live out these kinds of lifestyles it is not long before that country falls. Thus was the case of Babylon.
Enter Persia upon the scene. Persia was now to receive Its chance to choose to follow God.