The Spanish Civil War: Stages, Evolution, and Key Events
The Spanish Civil War (1936-1939)
The Military Uprising and Outbreak of War
Following the Popular Front’s victory, a broad group of monarchists and conservatives (including Sanjurjo, Mola, Fanjul, and Franco), alongside groups like the Falange and the Carlists, orchestrated a military conspiracy. While their shared goal was to overthrow the Republic, there was no unified vision for the post-republican regime. The assassination of Calvo Sotelo on July 12, 1936, served as the pretext for the uprising.
General Mola coordinated the conspiracy, but the uprising commenced on July 17th when the army, led by Franco, rebelled in Morocco. Initially, the mainland underestimated the severity of the situation. However, by the following day, military leaders in sixteen provinces had joined the rebellion, including most of Andalusia (Queipo de Llano in Seville), parts of Aragon and Navarra (Mola), Castilla y León (Davila), and Galicia. The uprising failed in Madrid, Catalonia, the Basque Country, Valencia, Castilla-La Mancha, Extremadura, and Asturias. This marked the beginning of a three-year civil war that divided Spain into two zones: the Republican zone and the Nationalist zone.
Stages of the War
Stage 1: Crossing the Strait (July 1936)
Both sides recognized the strategic importance of Madrid, making it the insurgents’ primary target. Franco aimed to swiftly transport his army from Morocco to the mainland, utilizing Italian and German aviation (as the Spanish fleet remained loyal to the Republic). Within a week, Franco had assembled 14,000 well-armed and trained troops on the peninsula, demonstrating unwavering loyalty to him.
The initial government led by Casares Quiroga and Martínez Barrio (July-September 1936) resigned after refusing to arm the people, fearing a potential revolution. José Giral took power and armed the populace, but his inability to control the situation led to his resignation in September 1936.
Stage 2: The Battle of Madrid (September 1936 – March 1937)
The Nationalist forces attempted to encircle Madrid. Mola advanced from the north, while Franco’s southern advance was slower due to the need to capture Badajoz and relieve the siege of the Alcázar of Toledo, where Moscardó’s forces resisted the Republican siege (an event magnified by Francoist propaganda).
Madrid resisted fiercely, defended by the loyalist army and militia. The Nationalist leaders decided to isolate Madrid from the rest of Republican Spain, establishing a siege. However, the siege was broken at Jarama (February 1937) and Guadalajara (March 1937). The city endured heavy bombing by Italian and German aircraft, but it held firm under the slogan “No Pasarán!” (They shall not pass!). The Nationalist leaders then shifted their focus to other strategic areas.
In a parallel effort to relieve pressure on Madrid, the Republicans concentrated their forces in Aragon but failed to capture any of the Aragonese capitals due to a lack of unified command and discipline.
During this stage, the government was led by Largo Caballero (September 1936 – May 1937) of the UGT. It was a coalition government comprising Republicans, Socialists, Communists, and Anarchists. Largo Caballero’s fall was triggered by the May 1937 crisis in Barcelona.
Stage 3: The Northern Campaign (April-October 1937)
The Nationalists targeted the Cantabrian coast, which was isolated from the rest of Republican Spain and possessed valuable mining and industrial resources. The German Condor Legion played a significant role in this campaign, notably in the bombing of Guernica, where 70% of the city was destroyed. Bilbao and Santander fell in June, followed by Gijón in October after a staunch defense by the miners.
The Republicans attempted to relieve pressure on the north with an offensive at Brunete in July 1937, but they failed to lift the siege of Madrid or prevent the collapse of the northern front.
Stage 4: The Aragon Campaign (September 1937 – Fall 1938)
As the war progressed, a sense of defeatism spread among Republicans. To boost morale, the Republican command launched an offensive in Aragon. In December 1937, the Republican army, supported by the International Brigades, captured Teruel. However, a Nationalist counteroffensive in February 1938 retook the city, leading to the resignation of Defense Minister Indalecio Prieto, who was replaced by Juan Negrín.