Creating an independent republic was a process of experiment, debate and compromise across the states and their delegates. The Continental Congress adopted the Articles of Confederation, which united the 13 original states but lacked centralized authority. In 1787, states called a Constitutional Convention to revise and amend the Articles. Instead, the Convention produced a new agreement of union––the U.S. Constitution. Opponents to the Constitution, fresh from the struggle against tyranny, insisted on protecting individual liberties, including the freedoms of speech, religion and assembly. In 1789 Congress proposed 12 amendments to the original U.S. Constitution. Ten of these were ratified by the states and became known as the Bill of Rights.