Why did the Congress of Vienna redraw the boundaries of some European countries?

The main goal of the congress of Vienna was to keep a lasting peace in Europe. To do this, they created the principle of legitimacy which restored all monarchs to the throne who were in power before Napoleon, which is a very conservative law. Some boundaries were drawn for the same reason, and others to keep European balance of power, which means that one country should not be stronger than another.

To encircle France with strong countries.