A French moralist, writer and philosopher, a precursor of sociology and a major figure of the Enlightenment. Even though born into nobility and a family of magistrates, Charles-Louis had a beggar designated as a godfather: his parents wanted to help him understand that the poor were part of the family. After studying law, he became an advisor to the Bordeaux Parliament but quickly began a process of reflection which led him to take an interest in the sciences, philosophy and human societies. His Persian Letters (1721) ironically depicted a French society discovered by Persian travellers. It was after numerous extended voyages in Europe that he wrote his major work, The Spirit of the Laws (1748). Despite the attacks he was subject to, notably by the Church, which banished him and placed him on the Index, the book was an immense success which extended throughout the whole of Europe. In it Montesquieu expounds the fundamental principles of economic and social sciences. He endeavoured to explain the logic of different political systems and institutions and, above all, advocates a political model which consecrates the principle of the separation of the legislative, executive and judicial powers. Very critical of French absolutism and monarchism, he called for – in vain – reforms inspired by the British constitutional monarchy. Montesquieu’s works greatly inspired the 1787 American constitution and the 1791 French constitution, springing from the 1789 Revolution. The principle of the separation of powers has been consecrated in the majority of the fundamental laws of modern democracies.