Spanish Civil War: Origins, Battles, and Outcome

1. The Military Uprising and Internationalization

The political climate of Spain, following the February 1936 elections, was tense. The murders of Lieutenant Jose Castillo of the Assault Guard and subsequently Calvo Sotelo provided a catalyst for a pre-existing military plot to overthrow the Republic. In July 1936, the garrison in Melilla revolted, and the rebellion spread across Morocco and mainland Spain. This triggered a three-year civil war, fueled by several factors:

  • The defense of the Republic by a significant portion of Spanish society.
  • The initial failure of the military coup in major cities.
  • International intervention, with both sides receiving external support.

Spain became divided between two opposing ideologies. The self-proclaimed “Glorious National Uprising” aimed to save Spain from anarchy, restore order, and eliminate perceived enemies of the nation. Conversely, those loyal to the Republic fought to defend democratic gains and resist fascism. For many Spaniards, allegiance was determined more by geography than ideology.

The Republic retained control of most mining and industrial areas, as well as financial resources, including Spain’s gold reserves. While exact figures are unavailable, approximately 116,501 men remained loyal to the Republic, compared to 140,604 on the rebel side. Of sixteen thousand officers, only about 3,500 sided with the Republic. Spontaneous militia leaders emerged, some commanding thousands of men. The Republican Army initially faced a disadvantage due to the government’s order for soldiers not to obey their officers, necessitating the creation of a new army incorporating militias and deserters. The rebel faction was bolstered by Carlists and Falangists, well-armed and disciplined. The upper and middle classes generally supported the uprising, while the working classes and urban populations supported the Republic. Geographic loyalty was a significant factor, with the autonomous governments of the Basque Country and Catalonia supporting the Republic. In Madrid, the government was led by Socialist Largo Caballero, with Manuel Azaña as President of the Republic.

The Civil War might have ended within six months due to equipment shortages on both sides. France and Britain established a Non-Intervention Committee, including 30 countries, but in practice, both sides received international aid. The Republic received military aid from the USSR, and to a lesser extent, from France and Mexico. This Soviet support led to the Republic being increasingly associated with communism in international public opinion. The International Brigades, composed of volunteers from thirty countries, provided humanitarian and military assistance, famously declaring, “Spain will be the tomb of fascism.” The rebel side received substantial aid from Italy and Germany, including the Condor Legion. Portugal also provided military support. The United States remained officially neutral, but many individuals, companies, and bankers aided the rebels. Soviet aid to the Republic was limited in quantity and quality, partly due to the looming threat of World War II.

2. The Development of the War

The military conflict progressed through four major stages:

  • The rebel advance towards Madrid.
  • The battles around Madrid and occupation of the North.
  • The offensive towards the Mediterranean.
  • The Battle of the Ebro and the end of the war.

A) The Rebel Advance to Madrid

Military operations began the week following the uprising, initially characterized by the use of columns. This phase lasted until the rebels’ failed attempt to capture Madrid. African troops linked the northern and southern rebel zones after overcoming resistance in Badajoz. Franco captured Toledo and reached the outskirts of Madrid by late October. The fall of the capital seemed imminent, prompting a general mobilization and the relocation of the Republican government to Valencia, leaving Madrid under the control of a board led by Miaja. Despite air raids, Madrid resisted, partly due to the arrival of the first International Brigades and an anarchist column from Barcelona.

B) The Battles Around Madrid and Occupation of the North

This phase saw the reorganization of both armies. The Republic created the People’s Army, militarizing or dissolving many militias. Franco also militarized his volunteer corps. The rebels launched two offensives to encircle Madrid. The Battle of Jarama resulted in both sides claiming victory. At the Battle of Guadalajara, Italian fascist troops allied with Franco suffered a significant defeat, marking the first major Republican victory. Franco then shifted his strategy, focusing on the northern Cantabrian strip. The rebels, led by Mola, attacked Vizcaya in late March. Guernica was destroyed by Nazi aviation. Bilbao fell due to the rebels’ superior weaponry and air power. The Republic launched counteroffensives at Brunete and Belchite, but failed to prevent Franco’s troops from capturing Santander and then Asturias. This loss of a key industrial area led to a mass exodus of refugees to Republican-held territories, particularly Catalonia.

C) The Offensive to the Mediterranean

By December 1937, the Republican army had been restructured. The aim was to strengthen the military organization and improve its effectiveness. The new Republican Army attempted to seize the initiative, launching several offensives, most notably towards Teruel. The ensuing Battle of Teruel resulted in the temporary Republican occupation of the city. Franco’s army then launched a campaign through Aragon, crossing the Maestrazgo and reaching the Mediterranean at Vinaroz. This divided the Republican territory into two zones, one being Catalonia. Franco could have ended the war at this point but chose not to, possibly to avoid approaching the French border during a period of international tension. He continued his offensive south, engaging in heavy fighting around Castellón and Valencia. His advance was halted when the Republican army launched a powerful attack on the Ebro River in Tarragona.

D) The Battle of the Ebro and the End of the War

The final phase of the war began with the Battle of the Ebro, one of the largest military engagements of the conflict. The Republican offensive initially achieved deep penetration south of Gandesa, which they managed to hold for several months. Franco eventually halted the attack and launched a counteroffensive. By early November, the Republican army had retreated across the river, and Franco’s forces advanced across the river mouth. The battle ended on July 16. Franco then launched a decisive offensive against Catalonia. Barcelona fell in January. The fall of Girona led to a mass exodus of refugees, including the Republican government, to France. By early February, all of Catalonia was occupied, effectively sealing the fate of the Republic. By February 1939, the Republic controlled only the Central Zone (Madrid and the Mediterranean region from Valencia to Almería). England and France recognized Franco’s government, and Manuel Azaña resigned. In early March, a military uprising against the Republican government, led by Casado, occurred in Madrid. Casado, who had been in contact with enemy intelligence, believed that Communist influence was prolonging the war and sought to negotiate a peace with Franco. He seized control of Madrid after fighting with Communist units. With some support from Socialists and the UGT, he formed a Defense Board to negotiate an honorable surrender with Franco, based on terms of leniency. Franco, however, refused to accept any conditions. In the days following the entry into Madrid, Franco’s forces occupied the entire Mediterranean area. On April 1, Franco signed the last war dispatch in Burgos, officially ending the Spanish Civil War.