Which document became the United States Constitution's first ten amendments in 1791?

The Bill of Rights became the United States Constitution's first ten amendments in 1791.

Congress proposed twelve amendments in 1789, following concerns that the new federal government might threaten individual and state liberties. The states ratified ten of those proposals, and they took effect on December 15, 1791.

The amendments protect rights including freedom of religion, speech, press, assembly, and petition. They also address criminal procedure, weapons, quartering soldiers, and powers retained by the people or the states. The two proposals not adopted at the time concerned congressional apportionment and congressional pay.