Charles-Louis de Secondat, Baron de La Brède et de Montesquieu (/ˈmɒntɨskjuː/; French: [mɔ̃tɛskjø]; 18 January 1689 – 10 February 1755), generally referred to as simply Montesquieu, was a French lawyer, man of letters, and political philosopher who lived during the Age of Enlightenment. He is famous for his articulation of the theory of separation of powers, which is implemented in many constitutions throughout the world.