Bill of Rights
The Constitution was ratified without an explicit guarantee of individual rights. During the Constitution’s ratification debates, the absence of a bill of rights was one of the most heated issues. The First Federal Congress took up the matter and proposed twelve articles to the states for ratification. Ten of the twelve proposed amendments to the Constitution were ratified by the required number of states; they became part the Constitution on December 15, 1791.
National Archives, General Records of the U.S. Government