The Bill of Rights was added to the Constitution as a conciliatory measure between rival ideological factions active during the Constitutional Convention and subsequent state ratification. Most importantly, it addressed individual liberties that were not adequately addressed in the Constitution itself.
In the years following the American Revolution, there was sharp disagreement as to what powers a national government might hold, should one even be agreed upon. While Federalists championed the need for strong national institutions, many were wary that a strong central government could eventually prove no better than the abusive monarchy the new states had just cast off. When the main body of the Constitution was finally finished, many Anti-Federalists continued to believe that the powers granted the new federal government were still too extensive or too vague. Hence, the Bill of Rights was proposed as an explicit safeguard for individual freedoms at the behest of Anti-Federalists such as Patrick Henry, Samuel Adams and Richard Henry Lee.
The rights outlined in the new bill strongly reflected the ideological values of the leading revolutionary intellectuals and their allegiance to concepts of natural rights universal to all humankind. The rights to free speech, demonstration and profession of religion are among the most celebrated. Additionally, the new bill guaranteed speedy and impartial jury trials, freedom of the press, freedom from unreasonable search and seizure, and the right to bear arms.