What were the main causes and consequences of the French involvement in the First Carlist War?

The First Carlist War was a conflict that took place in Spain between 1833 and 1840, fought between two factions that supported different claimants to the Spanish throne. One of the factions, known as the Carlists, was led by Carlos de Borbón, who claimed the throne as the rightful heir of the Spanish monarchy, while the other faction supported Queen Isabella II.

The French involvement in the First Carlist War was driven by a desire to protect its interests in Spain and to prevent the spread of political instability to neighboring countries. In 1834, France signed a treaty with Queen Isabella II, agreeing to provide military support in exchange for certain economic concessions.

French intervention played a key role in the outcome of the war. French troops helped to suppress the Carlist rebellion and secure the victory of Queen Isabella II. However, French intervention also had significant consequences for Spain and for French foreign policy. It left a legacy of resentment in Spain, where many people saw French intervention as an unwelcome intrusion into Spanish affairs. It also strained Franco-British relations, as Britain viewed French intervention as a threat to the balance of power in Europe.