One of the principal points of contention between the Federalists and Anti-Federalists was the lack of an enumeration of basic civil rights in the Constitution. In several states the ratification debate hinged on the adoption of a bill of rights. The solution was known as the Massachusetts Compromise, in which four states ratified the Constitution but at the same time sent recommendations for amendments to the Congress.
James Madison introduced 12 amendments to the First Congress in 1789. Ten of these would go on to become what we now consider to be the Bill of Rights. One was never passed, while another dealing with Congressional salaries was not ratified until 1992, when it became the 27th Amendment. The Bill of Rights contains rights that many today consider to be fundamental to America.
Source: Bill of Rights
The White House, usa.gov