The first ten amendments became the United States Bill of Rights in 1791.
Congress proposed 12 amendments on September 25, 1789, largely through the efforts of Representative James Madison. The states did not ratify all 12. Articles Three through Twelve were approved by the required number of states on December 15, 1791, becoming Amendments One through Ten.
The Bill of Rights was created partly in response to Anti-Federalist concerns about the new Constitution. It protects freedoms including speech, religion, the press, assembly, and due process, while also addressing limits on federal power.
A common mix-up is saying that Congress proposed only ten amendments. It actually proposed 12; two failed to receive enough state approvals at that time. One of those later became the Twenty-Seventh Amendment in 1992, while the other remains unratified.