Liberalism began during the Age of Enlightenment and rejects many assumptions that dominated earlier types of government, such as the Divine Right of Kings, hereditary status, and established religion.
The US for example was effectively the first modern liberal state, founded without a monarch or a hereditary aristocracy.
Writing the Bill of Rights guaranteeing rights of the People was a VERY Liberal minded thing to do!
Liberalism is the belief in the importance of individual freedom, it drives me insane to hear right wingers talk about Liberals as the enemy of America, when the country was started by them in the first place!