Queen Isabella II of Spain (10 October 1830 – 9 April 1904) was barely three years of age when her father, King Ferdinand VII, died on 29 September 1833. The years of her minority were marked first by the regency of her mother, Maria Christina of the Two Sicilies, and then under General Baldomero Espartero, covering almost the first ten years of her reign, until 23 July 1843, when Isabella was declared to be of age.

Upon the death of Ferdinand VII, his wife Maria Christina immediately assumed the regency on behalf of their daughter, and promised the liberals a policy different from that of the deceased king. A large part of Spanish society hoped for political reforms once Isabella II came of age that would reflect the liberal models that had developed in some nations of Europe. The First Carlist War and the confrontations between the liberals of the Moderate Party and those of the Progressive Party culminated in the rise to the regency of General Espartero, in a convulsive period plagued by governmental crises and social instability.

In the UK, William IV oversaw profound liberal reforms which made Parliament the real political engine of the country. After the defeat of Spain in the Battle of Trafalgar, the extension of what would soon become the British Empire began to take shape, especially from 1837 with the accession of Queen Victoria to the throne. Democracy was established in the country as an unquestioned model.

On the continent, with the dissolution of the Holy Alliance in 1830, France had overthrown absolutism with the fall of Charles X and established a constitutional monarchy in the person of Louis-Philippe d'Orleans, under whose rule the Industrial Revolution was launched and the bourgeoisie took the reins of the national economy.

Absolutism was relegated to Prussia, Russia and Austria, although in the former the impulses of unification with the German Customs Union, nourished by the liberals, who will not cease to obtain partial successes in the commercial field, will open the borders and will procure advances in the new pre-industrial society.

The death of Ferdinand VII provoked a series of uprisings and the proclamation of Don Carlos as king. The uprisings were led by absolutist military men who had been retired from the army or even prosecuted. The first to rise up was Manuel Martín González, followed by Verasategui, Santos Ladrón and Zumalacárregui. A bloody civil war began, characterized by its remote geographical locations, as it took place in the Basque Country and Navarre and in some small pockets in Catalonia, Aragon and Valencia.

Broadly speaking, the First Carlist War can be defined as the means to decide the continuity of the Ancien Régime or the triumph of liberalism.

Carlism defended absolutism. Among its ranks were the low rural nobility, the low Basque clergy and Basque and Navarrese peasants. The Carlists united under the cry of "God, Country and Fueros" (Spanish: "Dios, Patria y Fueros") (the defense of the Fueros begins in 1834 by means of an imposition of the Deputation of Biscay (Spanish: Diputación foral de Vizcaya) to Don Carlos).