Integrism is a Spanish political philosophy prominent during the late 19th and early 20th century. Rooted in conservative Catholic groupings like Neo-Catholics or Carlists, the Integrists represented the most right-wing formation of the Restoration political spectrum. Their vision discarded religious tolerance and embraced a state constructed along strictly Catholic lines.

The Integrists opposed Liberalism and the parliamentarian system, advocating an accidentalist organic regime. Led first by Ramón Nocedal Romea and then by Juan Olazábal Ramery they were active as a political structure named Partido Católico Nacional (also known as Partido Integrista), but the group retained influence mostly thanks to an array of periodicals, headed by the Madrid-based El Siglo Futuro. Though Integrism enjoyed some momentum when it formally emerged in the late 1880s, it was soon reduced to a third-rate political force and eventually amalgamated within Carlism in the early 1930s.

The role of religion and the Roman Catholic Church has been a point of heated political debate in Spain since the Napoleonic era, with waves of secularization and de-secularization following each other as the country was undergoing a half-century long, turbulent period of political instability. During declining years of the Isabelline monarchy of the 1860s different breeds of Liberalism sought to curtail the position of the Church still further. They were most vehemently opposed by two political groupings, both considered Integrist predecessors.

The so-called neocatólicos was an intellectual movement initiated during the early Isabelline years; its founding fathers, Juan Donoso Cortés and Jaime Balmes, tried to accommodate orthodox Catholicism within a framework of the liberal monarchy. With leaders like Antonio Aparisi, Cándido Nocedal, Francisco Navarro Villoslada, Gabino Tejado and Ramón Vinader, in the 1860s the neos strove to save the crumbling rule of Isabel II by building a grand, ultraconservative Catholic party. Their project crashed during the Glorious Revolution of 1868; in the early 1870s they concluded that the Liberal sway can no longer be confronted by constitutional monarchy and that a more radical response is needed.

Carlism emerged as an ultraconservative, anti-liberal and fanatically Catholic opposition to the Isabelline monarchy. Advocating the dynastic claim of another Borbón branch, the Carlists, nominally led by successive claimants, repeatedly attempted to overthrow Isabel II by means of military insurgence. Unlike the neos, from the onset they refused to accept the rules of constitutional monarchy and advocated the regime of a pre-modern kingdom. The Carlist ideology, though also very much centered on religion, was not exclusively focused on it; their ideario also comprised the defense of traditional regional establishments and dynastic claims. While neos remained mostly a group of urban intellectuals, Carlism was powered by popular rural Catholicism, which dominated some regions of Spain.

The revolution of 1868, the brief rule of Amadeo I, the emergence of the First Spanish Republic and especially another wave of militantly secular Liberalism drew the neocatólicos and the Carlists together. Starting in 1870 the neos, led by Antonio Aparisi Guijarro, began to join Carlist political structures and abandoned a separate political project of their own. Following the 1876 legitimist defeat in the Third Carlist War, with many traditional Carlist leaders being exiled or forced into seclusion, it was the former Neo-Catholics, usually not compromised by military action, who gradually started to emerge as leading pundits of semi-legal Carlism.

After death of Aparisi leadership of the group was assumed by Cándido Nocedal, already during the war the key Carlist representative on the Republic-controlled territory. As early as 1875 he set up the Madrid-based El Siglo Futuro which soon turned into a combative press tribune, formatted as the semi-veiled Carlism-leaning orthodox Catholic daily. Within Carlism, Nocedal represented the trend known as inmovilismo or retraimiento, pursuing abstention in official political life and trying to mobilize support along purely Catholic lines, like the massive 1876 pilgrimage to Rome. Prevailing over the competitive group known as aperturistas, in 1879 Nocedal was officially nominated the claimant's political representative and firmly focused Carlist activities on religious issues. Opposition to Pidalistas, the Traditionalists who – guided by the principle of Catholic unity – accepted the Restoration project in the early 1880s helped to format the Nocedalistas as religious intransigents; this was to be reflected in another pilgrimage, planned for 1882.

The course adopted by Nocedal and his son Ramón generated opposition within Carlism; many of its bigwigs grew anxious not only about Nocedals’ decisive leadership style but also because the movement had stalled in what they perceived was an ineffective intransigence and an apparent marginalization of other, traditional Carlist ideological threads. The conflict soon evolved into a bitter guerra periodistica, usually fought on religious grounds; titles supporting both factions claimed to have represented the genuine faith against the arbitrary usurpation of their opponents. The fray took a new turn when Cándido Nocedal died in 1885 and Ramón was not nominated his successor; the years leading to 1888 are marked by internal strife, decomposition and growing paralysis of Carlism.