It is limited to liberal and radical parties with substantial support, mainly proved by having been represented in parliament.
In the nineteenth century, liberalism was a major political force in Spain, but as in many other continental European countries care must be taken over the use of labels as this term was used with different meanings (this is discussed in the article on Radicalism (historical).
While all three rejected the Catholic, traditionalist, and absolutist Old Regime, each had a different perspective on the urgency and degree to which state and society needed reforming to modernize the values and institutions.
Each of the following sections describes an element of Spanish liberalism and radicalism, mostly beginning with the 19th century.
In the Contributions to liberal theory the following Spanish thinkers are included: