What Is Classical Liberalism? by Ralph Raico
"Classical liberalism" is the term used to designate the ideology advocating private property, an unhampered market economy, the rule of law, constitutional guarantees of freedom of religion and of the press, and international peace based on free trade. Up until around 1900, this ideology was generally known simply as liberalism. The qualifying "classical" is now usually necessary, in English-speaking countries at least (but not, for instance, in France), because liberalism has come to be associated with wide-ranging interferences with private property and the market on behalf of egalitarian goals. This version of liberalism – if such it can still be called – is sometimes designated as "social," or (erroneously) "modern" or the "new," liberalism.
Good history of liberal political thought.