The nineteenth century (1801-1900) began immediately after the upheaval of the American and French Revolutions. It started with the Napoleonic Wars, which were followed by the dramatic rise of the British Empire. Meanwhile, the United States was growing in power and size. In this context, political thought developed in multiple directions throughout the century. Tocqueville wrote his famous observations on American culture. John Stuart Mill, Lord Acton, and other British authors contributed to the development of political philosophy. Tolstoy and Thoreau advocated a political approach based on non-violence. Nietzsche and Hegel laid philosophic foundations for new views of politics, ethics, and history. The anarchist movement began, with works by Mikhail Bakunin, Pierre-Joseph Proudhon, and Peter Kropotkin.
During this period, too, the Industrial Revolution was rapidly changing the economic and social conditions of the Western world. The most important developments in political thought during this period were reactions to those changing conditions. Karl Marx and his companions proposed Communism as a comprehensive ideology, planting the seeds of numerous strands of political thought. Pope Leo XIII wrote on the questions of capital, labor, and liberty, setting the foundation for later Catholic social thought.