The first 10 amendments to the Constitution of the United States of America constitute the Bill of Rights. These 10 amendments were designed and ratified to prevent the federal government from becoming tyrannical and overly powerful. The inclusion of the Bill of Rights essentially guaranteed passage of the hotly-contested Constitution in 1789.
The idea for the Bill of Rights came from George Mason, a famous delegate to the Continental Congress from Virginia who rejected the Constitution as it was being presented because it lacked any declaration of rights at all. He helped pass the Virginia Declaration of Rights, which influenced James Madison to include many of its ideas in the first 10 amendments to the Constitution. George Mason's protest ended up affecting the nature of the American government as the Bill of Rights limited the power of government and augmented the freedoms of the individual and the states.