The United States Bill of Rights contains ten amendments to the Constitution.
The amendments were proposed by the First Congress in 1789 in response to concerns that the new Constitution did not sufficiently protect individual liberties. James Madison introduced the proposals, drawing partly on state declarations of rights and arguments raised during the ratification debate.
Congress originally proposed twelve amendments, but the states ratified only ten of them in 1791. The first proposed amendment, concerning the size of congressional districts, was not ratified at that time. The second proposed amendment, concerning congressional pay, was eventually ratified centuries later as the Twenty-seventh Amendment in 1992.
The ten amendments that became the Bill of Rights address freedoms such as religion, speech, press, assembly, and petition. They also cover protections involving searches, criminal prosecutions, juries, and reserved powers. The Bill of Rights is therefore not a separate document from the Constitution, but its first ten amendments.