What is the purpose of the Bill of Rights?

The original framework for the country, the Articles of Confederation, was a weak structure, probably in response to the authoritarian government the Colonies just freed themselves from. It was found that this was too weak of a governing system. The Constitution brought a stronger central government but anti-Federalists, like Madison, thought there were not sufficient checks on governmental power. The Bill of Rights fixed this. It enumerated specific natural rights, gave protection to those that weren't specifically enumerated (9th) and put a limit on the power of the federal government (10th).