Classical liberals believe in a small government, and believe that people will be ruled mostly by natural law. They believe that people have inalienable rights. They also believe in a free market and property rights.
Notable people who developed classical liberalism during the 18th and 19th century are Adam Smith, Thomas Malthus and Thomas Jefferson. More recently, in the mid-20th century, Ludwig von Mises, Friedrich Hayek and Milton Friedman were in favor. Many of the beliefs of classical liberalism are similar to those of libertarianism.