Many twenty-first century Americans believe that they have a God-given right to possess arms as a last resort against tyranny. One of the most important sources of that belief is the struggle for freedom of conscience in the United Kingdom during the reigns of Elizabeth I and the Stuarts. A moral right and duty to use force against tyranny was explicated by the Scottish Presbyterians George Buchanan and Samuel Rutherford. The free-thinking English Christians John Locke and Algernon Sidney broadened and deepened the ideas of Buchanan and Rutherford. The result was a sophisticated defense of religious freedom, which was to be protected by an armed people ready to resist encroachments on their natural, sacred liberties. The principle that right to arms is the ultimate guarantor of the right to free exercise of religion is one reason why the First and Second Amendments are placed next to each other in the American Bill of Rights.