The document established to protect individuals' rights in early American history is the Bill of Rights, ratified in 1791. This crucial set of amendments to the United States Constitution consists of the first ten amendments, outlining specific rights and freedoms guaranteed to the citizens. The Bill of Rights was created in response to concerns from anti-Federalists, who feared that a powerful central government might infringe on individual liberties. It encompasses fundamental rights such as freedom of speech, religion, assembly, and the press, as well as protections against unreasonable searches and seizures, ensuring a framework for civil liberties in the nation.