The covenant with Noah
This state of division into many nations, each entrusted by divine providence to the guardianship of angels, is at once cosmic, social and religious. It is intended to limit the pride of fallen humanity united only in its perverse ambition to forge its own unity as at Babel. But, because of sin, both polytheism and the idolatry of the nation and of its rulers constantly threaten this provisional economy with the perversion of paganism.
Source: Catechism of the Catholic Church (Vatican.va)