43: The War in the North


After the failure to take Madrid, the Nationalist shift their focus, and in their sights is the Republican Enclave in northern Spain.



  • The Battle for Spain by Antony Beevor
  • Spain in Arms: A Military History of the Spanish Civil War 1936-1939 by E.R. Hooton
  • The Spanish Civil War A Modern Tragedy by George R. Esenwein
  • Spanish Civil War Tanks: The Proving Ground for Blitzkrieg by Steven J. Zaloga
  • The Anarchist Collectives: Workers’s Self-management in the Spanish Revolution 1936-1939 Edited By Sam Dolgoff
  • Patterns of Development and Nationalism: Basque and Catalan Nationalism before the Spanish Civil War by Juan Diez Medrano
  • Blackshirts, Blueshirts, and the Spanish Civil War by John Newsinger
  • Edge of Darkness: British ‘Front-Line’ Diplomacy in the Spanish Civil War, 1936-1937 by Tom Buchanan
  • Franklin D. Roosevelt and Covert Aid to the Loyalists in the Spanish Civil War, 1936-39 by Dominic Tierney
  • The Cult of the Spanish Civil War in East Germany by Arnold Krammer
  • Fascism, Fascitization, and Developmentalism in Franco’s Dictatorship by Ismael Saz Campos
  • Writing the Female Revolutionary Self: Deoloris Ibarruri and the Spanish Civil War by Kristine Byron
  • A Spanish Genocide? Reflections on the Francoist Repression after the Spanish Civil War by Julius Ruiz
  • The Spanish Civil War in the 21st Century: From Guernica to Human Rights by Peter N. Carroll
  • The Revolutionary Spirit: Hannah Arendt and the Anarchists of the Spanish Civil War by Joel Olson
  • Seventy Years On: Historians and Repression During and After the Spanish Civil War by Julius Ruiz
  • Fascist Italy’s Military Involvement in the Spanish Civil War by Brian R. Sullivan
  • The Spanish Civil War: Lessons Learned and Not Learned by the Great Powers by James S. Corum
  • Truth and Myth in History: An Example from the Spanish Civil War by John Corbin
  • ‘Our Red Soldiers’: The Nationalist Army’s Management of its Left-Wing Conscripts in the Spanish Civil War, 1936-39 by James Matthews
  • Multinational Naval Cooperation in the Spanish Civil War, 1936 by Willard C. Frank Jr.
  • ‘Work and Don’t Lose Hope’: Republican Forced Labour Camps During the Spanish Civil War by Julius Ruiz
  • The Spanish Civil War, 1936-2003: The Return of Republican Memory by Helen Graham
  • Soviet Armor in Spain: Aid Mission to Republicans Tested Doctrine and Equipment by Colonel Antonia J. Candil, Spanish Army
  • The Soviet Cinematic Offensive in the Spanish Civil War by Daniel Kowalsky
  • Soviet Tank Operations in the Spanish Civil War by Steven J. Zaloga
  • The Spanish Military and the Tank, 1909-1939 by Jose Vicente Herrero Perez
  • The Theory and Practice of Armored Warfare in Spain October 1936-February 1937 by Dr. John L. S. Daley


Hello everyone and welcome to History of the Second World War Episode 43 - The Spanish Civil War Part 8 - The War in the North. This week a big thank you goes out to Jacqueline for the donation and to MJ for their support on Patreon, where they get access to ad free versions of all of the podcast’s episodes plus special Patreon only episodes released once a month. If that sounds interesting to you head on over to historyofthesecondworldwar.com/members to find out more information. After the failure of the attack on Madrid the decision was made to shift Nationalist resources to another area of the front. One option, and the one chosen, was an attack against the Republican northern enclave. This area had remained under Republican control on the northern coast of Spain and was about 300 kilometers across, but only about 35 kilometers deep. It contained most of the modern Spanish provinces of Vizcaya, Cantabria, and the Eastern half of Asturias. However, within the reasonably small space there were 1.5 million people and about a 1/3 of Spanish industrial capacity. During 1936 Nationalist forces had captured Irun on the French border which cut the Northern Enclave off from receiving supplies from France, which meant that everything had to be brought in by sea. General Mola had always been in favor of targeting the enclave and after the events of early 1937, and particularly the failures of the various offensives aimed at isolating Madrid, Mola presented the plan for the attack in the north to Franco. This presentation was made on March 20th, but Franco did not immediately approve. There were many things to consider, even those outside of strict military objectives. Mola was still seen as a possible political rival, and putting another campaign under his command, and one that would probably be successful, would boost his prestige. However, Franco was eventually convinced to shift resources north by Juan Vigon, a staff officer who would be the Chief of Staff for what would become known as the War in the North. The eventual success of the attacks in the north would eventually get Vigon promoted to General.

Within the northern enclave, which was largely isolated from the rest of the Republic, there were three different governments, and three different armies. Furthest east and the first to be targeted by the Nationalist attack was the Basque country, which was structured as a self-contained state. The Basques had long been seeking greater autonomy, and assurances of that autonomy had been one of the reasons that they continued to support the Republic. It was clear that if they wanted to see that autonomy they needed to be able to defend themselves from a Nationalist attack, and to try and mount that effective defense they would raise 46 battalions of troops. This was made up of both Basque militias and then militias created by the CNT, UGT, and Communists. The problem for the Basque leadership was not so much finding people to fight, but instead finding equipment and then keeping them fed. Food was a serious concern, not just for the military but also for the people who lived in the enclave, and for the entire existence of the enclave there would never ben more than a few weeks worth of food available. Shipping moved in and out of the area, but it was never enough to both provide for the basic necessities of life and to equip the militia forces. By the time of the Nationalist attacks they had managed to bring in some tanks, machine guns, and aircraft, as well as a large number of rifles, but it was clear that they would be at a equipment disadvantage if the Nationalists shifted resources north. To try and supplement the men and weapons that were available the Basques began to construct a line of defensive fortifications. This series of fortifications would be known as the Iron Belt, and it was over 70 kilometers long. The plan was for the Belt to surround the capital of Bilbao with 1400 concrete pillboxes, troop shelters, trenches, and barbed wire. This required a huge construction effort and at its height over 15,000 men were working on the defenses. But even with all this manpower, the terrific length of the Iron Belt very quickly began to cause problems. To make the fortifications as long as they needed to be they also had to quite thin, and most of them were arranged at only a kilometer in depth. In the context of defensive fortifications at this point in history this was simply not deep enough and put all of the defenses at risk to enemy artillery. Even with these compromises made, the thin veneer of defenses were only about a quarter of the war complete when the Nationalist attack was launched. This left terrific gaps in the defenses, and made what was completed incredibly vulnerable. To add to these problems, the Nationalists knew most of the details of the Iron Belt and this emboldened Mola in his planning for its eventual destruction.

When planning their attack the Nationalists had several advantages, they had more organized troops, and were experiencing none of the supply shortages of the Republicans. They also would enjoy almost complete air supremacy over he enclave, and it would become the primary area of operation for the German Condor Legion during the campaign. When it came to their ground attack the Nationalist plans were in many way dictated by geography. There was mountainous terrain that restricted the possible options in terms of attack routes and so after choosing their first major objective of Bilbao they were restricted to passing through the river valleys that converged on the city. There would be three attacks down these values which would originate in Vergara, Villareal, and Orduna. If you look at a map these three paths were positioned between the 3 o’clock and 6 o’clock positions if the clock was centered on Bilbao. The advance from Villareal, the center of the three, was given priority and the majority of the troops. In total the attack would be under the command of General Mola with the northern army over over 100,000 men. At the forefront of the attack was the Navarre Division which was made up primarily of Carlist forces, with the Black Arrows Division of Italian troops also being present and involved. The official orders were sent out on March 29th for the attack to begin on the 31st. An ultimatum was provided to the Basque leaders before the attack began, with Mola stating that ‘if submission is not immediate I will raze Vizcaya to the ground.’ With the ultimatum rejected, the attack would begin at 9:40AM on March 31st. It would begin with an extensive artillery barrage and bombing raids with the goal of isolating the forward Republican troops. This was mostly successful, and it would be difficult for additional defending troops to be brought into action before the Nationalist infantry began to push forward. A combination of a determined attack by Carlist infantry and a general feeling of helplessness against air attacks was a demoralizing combination for the defenders. By April 5th the attack had pushed forward 15 kilometers on a front 20 kilometers wide. However, due to the terrain they were unable to widen this salient and the offensive began to stall. After this stall occurred on April 6th the Nationalists announced that they would be blockading the Republican ports on the coast with their available naval assets. This announcement caused concern not just among the people within the enclave that depended on that shipping for food and supplies but also among foreign governments. For example in London the British were concerned due to their public statements and guarantees of non-intervention. There were Royal Navy ships in the Bay of Biscay and there were frequent visits to Bilbao by British merchant ships. To avoid any possible issues the military vessels were moved into the French port of Saint Jean de Luz, with all other British flagged ships told to follow suit. However, not all British merchant ships followed these orders and on April 20th the Seven Seas Spray would ignore them and sail from Saint Jean de Luz to Bilbao. This caused a bit of embarrassment for the British government, and more importantly broke the flood gates and other vessels would follow the Seven Seas Spray’s example. This meant that Bilbao would not be starved into submission, and some supplies would continue to be brought in by sea, however the amount of shipping moving into the port was reduced, and what was left did little to prevent the resumption of the Nationalist land offensive.

Also on April 20th the offensive began again, after another round of artillery of course. This attack based based around pushing from east to west and a combination of the artillery, Nationalist air power, and the completely inadequate nature of Basque entrenchments pushed the defenders to the point of collapse. There were several instances of units moving out of the line without warning or orders to do so as the collapse began. Then on April 25th, one of the most infamous events of the war would occur. In the late afternoon in the town of Guernica church bells began ringing to warn of an air attack. People began to move into pre-arranged air raid shelters and at around 5PM aircraft were spotted overhead, and the bombs started falling. Several squadrons of German bombers were assigned the mission of bombing the city first to cut off various routes out of the city being used by military forces, and then as direct terror bombing of civilian targets which would last for hours. Hundreds of people would be killed and many more wounded. Huge amounts of the town were destroyed, strictly for the purpose of terrorizing both the people and soldiers in the area and all those left within the enclave. The destruction of clearly civilian targets would become one of the main talking points of the events in Spain. The indiscriminate bombing of cities would become common place in later years, but in 1937 this was new and unique. At a time when fears of aerial bombing were at an all time high in several nations, it fed into existing fears. The Republican leaders then fed into this by greatly exaggerating the number of people killed in the attack, claiming the number was as high as 1,700. The clear presence of German aircraft put additional strain on the official non-intervention policies of Britain and France, although not enough to force them to make changes. The bombing of Guernica, and the death and destruction it would cause, would go on to be one of the most lasting international legacies of the war and was seen as a moment marking a new age of warfare that would be greatly amplified during the Second World War.

In early 1937 it would mark neither the beginning or the end of the attacks in the north, and the offensive would continue. During May more Nationalist troops would be brought north, greatly expanding the forces available as each of the four Navarrese brigades were increased in size and several thousand more Italian troops were also added to the attack. The advance continued until on May 22nd the troops began to reach the Iron Ring set of defenses. On June 3rd, before a new round of attacks could begin General Mola was killed in a plane crash. Mola had been one his way to meet with Franco to discuss the future course of the campaign, but his plane would crash in the Brujula mountains near Castile de Peones with the deaths of all on board. This was one of the reasons that Franco would avoid air travel for the rest of his life. Mola’s position was filled by General Davila with Colonel Vigon made his chief of staff, and this duo would stay together for the rest of the war. When looking at the defenses in front of the Nationalists Vigon would decide to target the area around Mount Gaztelumendi, in that area the defenses were forced into a sharp angle and they were not well developed. Remember that even after the huge amount of effort that was put into the Iron Ring defenses they were far from complete, and in this area they had serious weaknesses. The Nationalist assault would move against the defenses from both the north and the south and would include 144 artillery pieces and 100 aircraft. The initial plan called for the attack to begin on May 28th, but weather would intervene and it would prove to be impossible to launch the attack for two weeks. In attempting to marshal a defense the Basque forces were largely demoralized and weakened units that had been retreating since the offensive began. They were not completely beaten, and there were some solid rearguard actions as they had been forced to retreat, but they were heavily dependent on the ability of the prepared defenses around Bilbao to give them the strength to stop the advance. The constant issue that would continue to be present was the Nationalist domination of the air, which the Republicans had very little answer for. this become a greater and greater problem for morale as the offensives continued and events like the bombing of Guernica would occur. There were attempts to assist the forces within the Enclave, for example Republican aircraft would be sent from eastern Spain, however they were forced to fly around Nationalist territory and over French territory if they wanted to make it to the enclave. This long distance, much of it over mountainous terrain with uncertain weather, while also trying to dodge non-intervention patrols, meant that out of the 50 aircraft that were sent only 20 would actually make it to Bilbao successfully and intact. There were other ways in which the Republican leaders in Valencia attempted to the defenders in the north. Two attacks would be launched in May, the Huesca offensive and an attack in the Sierra de Guadarrama. Neither of these attacks would be greatly successful, or accomplish their greater goal of pulling Nationalist troops away from the attacks in the north. Along with attempts to assist, there were also concerns in Valencia that the Basque forces needed a new leader, and so Brigadier General Mariano Gamir, a Basque officers, was put in command. He would fly into Santander on May 29th and begin an inspection of the situation. What he found were units that had been drastically reduced in size due to the losses suffered over the previous months of fighting. A week later he would inform Valencia that given the state of the troops and the acute shortage of equipment he had little faith that Bilbao could be defended. The only thing really delaying the inevitable was the weather, which during the last half of May an early June would continue to prevent another Nationalist effort. However eventually the weather would break and Davila would order the assault to begin on June 12th.

The attack would begin after a 7 hour artillery barrage. As in earlier attacks this had a devastating effect on large portions of the defenses, especially the inadequate shallow trenches that made up the majority of the defenses. Very quickly there was first a 2 kilometer and then a 5 kilometer gap in the defenses and the Nationalists continued to push through. As it became clear that the defenses around Bilbao were not going to stop the attack the Basque government evacuated the city on June 16th. They would move to Villaverde de Trocios in Santander while others would evacuate to France by air. As in Madrid the previous year a Junta de Defense was setup, and put under the command of the Minister of Justice Leizaola. However unlike Madrid there was little hope in the defense, and the city was under constant artillery bombardment. Because the defense seemed doubtful it immediately became apparent that the troops would either need to evacuate or risk being cut off by Nationalist attacks moving up from the south to the west of the city. This prompted an order for all remaining military units to withdraw from the city at dawn on June 18th. Even the retreat was dangerous as Nationalist air attacks put the troops at constant risk. On June 19th around Bilbao white flags were raised and put outside windows and even some Nationalist flags were seen to be flying. Neither of these efforts prevented a series of arrested and violence against the inhabitants of the city. With thousands executed. The capture of the city, and then the rest of Vizcaya left the Nationalists in control of some very valuation industrial resources. It had cost them about 30,000 casualties, roughly the same as those suffered by the defenders, with around 4,500 dead for the Nationalists and over 10,000 dead among the Basque forces. Many of the Basque troops, who had volunteered to defended their homes, deserted or surrendered rather than follow the rest of the forces in their retreat to the West. The main Basque forces retreated into Santander along the coast, but there was little to prevent a complete collapse of morale. In total military forces available for the defense of Santander were only about 80,000 and they would still possess little ability to prevent complete Nationalist control of the air, with only 40 operational aircraft available.

The initial Nationalist plan was to immediately roll into an attack into Santander, with Franco sending out the orders to do so on June 22nd with an estimated start date of July 10th. These preparations were then interrupted by the Republican attack at Brunete on July 6th, an attack that we will discuss in Episode 10 of this series. This attack was finally able to distract the Nationalists from their attacks in the north and cause a pause of a month before the attack into Santander could begin. Two of the Navarrese brigades, along with aircraft on artillery, were moved south to meet the Brunete attack which occurred to the west of Madrid. However, by the end of the month these resources were sent back north and Franco ordered Davila to once again begin preperations for the final offensives against the northern enclave. Davila had spent the previous month revising and adjusting his plans, and settled on an attack along the coastal highway as well as an effort to cut off the Republican forces holding the Mataporquera salient. The existence of this salient, which was 25 kilometers deep, was probably a mistake by the Republicans as it was very exposed. The attack would begin on August 14th, and almost immediately they would experience success. After the initial artillery and air strikes the Nationalist forces smashed through the 54th division which was in place to block them. The situation with the Basque forces then began to deteriorate very rapidly. Instead of retreating west many units marched north to the coast, and in the port of Santona 22,000 would sign the Santona agreement which would allow them to surrender and take a ship out of the port. However, when Franco and Davila learned that local Italian officers had signed this agreement Davila immediately countermanded it. Instead the troops were forced back off the ships, and only wounded soldiers were able to stay aboard, the rest were destined for prison camps.

While many would be forced to surrender other troops would once against retreat to the west. Other would be trapped in Santander when the coastal road to Gijon was captured. Thousands would attempt to flea by sea, but only a few would do this successfully. Overall, the Nationalist victory in Santander was once again massive, with the huge material and morale superiority of the Nationalist forces simply overpowering what was in front of them. In total 86 battalions of troops from Asturias, Santander, and the Basque Army were destroyed, with 60,000 men taken prisoner. For this massive reduction in Republican forces in the north the Nationalists would only suffer about 2,900 casualties. What was left of the Republican military in the enclave would retreat into Asturias, where they hoped to be able to use the terrain to their advantage. They were trapped in a small area though, with it being just 125km across and 75km deep. Davila and Franco wanted the victory to be final, and they were determined to capture this are before the oncoming winter would force a pause that would last several months. On the first day of September the advance began again, with the same artillery and air preparations that had become a hallmark of the northern offensives. However, unlike during previous attacks the Republican resistance proved far more determined. Both the terrain and the weather was in favor of the defense with fog, rain, and a drop in temperatures thwarting Nationalist efforts. But it was still only a matter of time, on October 10th the town of Cangas de Onis was captured, which caused other areas to have to be quickly abandoned. This represented a turning point where the Republican resistance, which had been so tenacious during the early attacks in Asturias began to decline. On October 1`9th Villaviciosa was captured, bringing the Nationalists just 15km from the last Republican held city of Gijon. On the 20th that too was captured. For the entire War in the North the northern forces suffered 133,000 casualties. The Nationalists suffered 110,000, but for that price they were able to remove an important area of Republican control and gain access to 1.5 million people and one third of Spain’s industrial production capacity. Some irregular resistance would last for months in the mountainous areas of Asturias, but the campaign was finished and was a complete victory for the Nationalists. It allowed them to move over 100,000 troops to other theaters, and they would be used in a series of 1938 offensives.