The Age of Enlightenment was preceded by and closely associated with the scientific revolution. Earlier philosophers whose work influenced the Enlightenment included Francis Bacon, Descartes, Locke, and Spinoza. The major figures of the Enlightenment included Cesare Beccaria, Voltaire, Denis Diderot, Jean-Jacques Rousseau, David Hume, Adam Smith, and Immanuel Kant. Some European rulers, including Catherine II of Russia, Joseph II of Austria and Frederick I of Prussia, tried to apply Enlightenment thought on religious and political tolerance, which became known as enlightened absolutism. The Americans Benjamin Franklin and Thomas Jefferson came to Europe during the period and contributed actively to the scientific and political debate, and the ideals of the Enlightenment were incorporated into the United States Declaration of Independence and the Constitution of the United States.