The suppression of the Alt Llobregat insurrection in January 1932 led to the arrest and deportation of numerous anarchists, as well as an internal split within the Confederación Nacional del Trabajo (CNT).

But after contributing to the prevention of an attempted coup by General José Sanjurjo, the CNT experienced a resurgence in support and anarchist deportees were permitted to return to Spain.

Due to the slow, bureaucratic implementation of land reform and the regulation of trade unions by the new labour laws, workers' and peasants' dissatisfaction with the left-wing government increased.

By the time the insurrection broke out on 8 January 1933, leading anarchists had been arrested and the police were on high alert throughout the city, resulting in the uprising being suppressed by the following morning.

An investigation into the Casas Viejas incident found the government of Manuel Azaña culpable for the massacre, which caused it to lose support from the far-left and emboldened political opposition from the right-wing.

[1] In January 1932, a miners' strike in Central Catalonia escalated into a region-wide insurrection, during which workers proclaimed libertarian communism, before being suppressed by the Spanish Army.

[3] The suppression of the insurrection caused an internal conflict to break out within the CNT, as the moderate "treintistas" and radicals of the Iberian Anarchist Federation (FAI) blamed each other for the defeat.

[6] The CNT attempted to protest against new labour laws, introduced by the government on 8 April 1932, which regulated trade union activities and established works councils to resolve industrial disputes.

[14] The CNT, which had previously maintained a close relationship with the Republican Left of Catalonia (ERC) and had supported the referendum as a voting bloc, became more openly critical of Catalan nationalism after the Statute was passed.

[21] The Regional Federation of the CNT in Asturias attempted to call for dialogue between the two feuding factions, in order to find common ground between the FAI's insurrectionary position and the treintista emphasis on organisation, but the schism continued to deepen.

The only anarchist that freely organised was Valeriano Orobón Fernández, a member of neither faction of the CNT, who upheld industrial unionism and advocated for a popular front.

[25] On 1 December 1932, a rail strike broke out in Spain,[26] after Minister of Public Works Indalecio Prieto refused to raise the wages of railway workers.

As the FNIF believed the strike would result in repression against the workers, it called for an insurrection to prevent the government from consolidating its force, in a course of action recommended by a national plenum of the CNT.

[30] The Catalan Regional Defence Committee, under the influence of Joan Garcia Oliver, quickly grew frustrated with the reluctance of the CNT to take revolutionary action.

Garcia Oliver called for the CNT to begin practicing "revolutionary gymnastics", a kind of insurrectionary action intended to prevent the consolidation of the Republican government's forces.

Among the atendees were Domingo and Francisco Ascaso, Buenaventura Durruti, Aurelio Fernández, Miguel García Vivancos, Gregorio Jover, Juliana López, Pepita Not, Antonio Ortiz, Ricardo Sanz and María Luisa Tejedor.

[1] The group believed that conditions were right for an insurrection, as the Republican government was facing an increasing backlash against its land reform programme, while in Catalonia, President Francesc Macià was dying.

[35] Guerrillas operating in the city centre would occupy the telephone exchange, radio stations and Catalan government buildings, including the Palace of the Generalitat, Captaincy General [es] and Police Prefecture [ca].

They established an Andalusian Revolutionary Committee, headed by Vicente Ballester [es] of the CNT, Rafael Peña of the FAI and Miguel Arcas of the Libertarian Youth.

Between 21:00 and 22:00, these buildings would be blown up by autogenous welding tubes filled with dynamite, signalling to insurgent groups to begin their attacks against their selected targets using pistols and grenades, while revolutionary patrols were carried out in taxis.

[41] On 8 January 1933, at 08:00, two bricklayers pulled a small handcart loaded with bricks, cement and plaster, concealing two improvised explosive devices, onto Carrer dels Mercaders.

[39] Preempting the outbreak of disorder, the Spanish Army and police forces occupied positions where attacks were to predicted to happen and arrested CNT leaders on sight.

When Durruti led the assault against the Civil Guard barracks in Gràcia, his detachment found that the police had already mobilised, having been on high-alert since the workshop explosion in El Clot.

[34] According to the Valencian anarchist historian Josep Peirats, the Catalan Defense Cadres of the CNT-FAI had been poorly armed and put most of their hopes for success on the possibility of intervention by sympathisers in the military or the materialisation of strike actions by industrial workers, neither of which happened.

[30] On 10 January, the National Committee of the CNT declared the insurrection an event of "purely anarchist significance" which had not had the direct involvement of the organisation, although out of a sense of solidarity, they refused to outright condemn it.

Members of the secretariat of the International Workers' Association (IWA), including Alexander Schapiro and Eusebi Carbó [ca], concurred with this opinion, declaring that the success of a revolution is more dependant on mass support than the quantity of arms and explosives.

[30] At a meeting of the Madrid Regional Committee in late January, Mallada defended his initial editorial and called for independent attacks to be dropped, believing that the working class as a whole ought to determine when a revolution take place.

[66] In the Spanish capital, the Assault Guards surrounded the Local Federation building, arrested 250 members as they arrived and detained them in the General Directorate of Security [es].

[71] In April 1933, a formal inquiry into the Casas Viejas incident found Rojas directly culpable for the massacre, while Azaña, at the head of the chain of command, was also condemned for his role.

The right-wing opposition, led by José María Gil-Robles of the CEDA and Alejandro Lerroux of the Radical Republican Party (PRR), were emboldened to attack the government.