The Carlist Wars in Spain are the last major European civil wars in which pretenders fight to establish their claim to a throne.

At the beginning of the 18th century, King Philip V of Spain had promulgated the Salic Law, which declared illegal the inheritance of the Spanish crown by women.

His purpose was to thwart the Habsburgs' regaining the throne by way of the female dynastic line.

When Ferdinand VII of Spain dies in 1833, his fourth wife Maria Cristina beomes Queen regent on behalf of their infant daughter Isabella II.

This splinters the country into two factions known as the Cristinos (or Isabelinos) and the Carlists.

The Cristinos are the supporters of the Queen Regent and her government.

The Carlists are the supporters of Carlos V, a pretender to the throne and brother of the deceased Ferdinand VII, who denies the validity of the Pragmatic Sanction of 1830 that had abolished the semi Salic Law (he was born before 1830).

Several times during the period from 1833 to 1876 the Carlists — followers of Infante Carlos (later Carlos V) and his descendants — rally to the cry of "God, Country, and King" and fight for the cause of Spanish tradition (Legitimism and Catholicism) against the liberalism, and later the republicanism, of the Spanish governments of the day.

The First Carlist War lasts over seven years and the fighting spans most of the country at one time or another, although the main conflict centers on the Carlist homelands of the Basque Country and Aragon, Catalonia and Valencia.