Conservatism has been one of the principal ideologies of the modern era. It was first articulated in its contemporary form in opposition to liberalism and specifically to the cataclysm of the French Revolution, which challenged the principles and values of the old order, and the authority of monarchs and priests. The deep-seated crisis of the European ancien régime, and the sudden appearance of revolutionaries prepared to act out utopian fantasies and inaugurate an entirely new kind of society, prompted a profound intellectual and political response, and laid the foundation for the modern conservative outlook.