The Bill of Rights is the collective name of the first ten amendments to the US Constitution. They were proposed on September 25th, 1789 and ratified into law on December 15th, 1791.
The Bill of Rights were originally proposed to meet concerns from a number of Constitutional delegates that the Constitution, while effectively laying out the foundation of the US government, contained no guarantee of rights for its citizens. These were men who had just fought a revolution against a tyrannical government, and they felt that simply enumerating the powers of a government was no true protection against the rise of another tyrant. A compromise was reached which allowed the original Constitution to pass, with the understanding that amendments would be made immediately after passage. There were originally 12 amendments proposed, but only ten were approved by the three-fourths majority of state legislatures needed to amend the Constitution. Many of the protections Americans take for granted come from the Bill of Rights. Free speech, freedom of religion, the right to a trial by jury, requiring a warrant to search a private home and the right to bear arms are just a few of the more important rights guaranteed by these amendments.