War in the North
Part of theSpanish Civil War
Map of the campaign
Date 31 March – 21 October 1937 Location NorthernSpain Result Nationalist victory Republican defeat in northern Spain
Belligerents
Spanish Republic Basque Army	Nationalist Spain CTV Condor Legion
Commanders and leaders
Adolfo Prada Vaquero Francisco Llano de la Encomienda Francisco Ciutat Francisco Galán Belarmino Tomás	Emilio Mola José Solchaga Fidel Davila Ettore Bastico
Strength
120,000 soldiers thousands of anarchistsmilicianos[1] 250 artillery pieces 40 tanks 70 aircraft 2 destroyers 7 armed trawlers	100,000 Nationalist soldiers 60,000 Italian soldiers[2] 400 artillery pieces 230 aircraft 1 battleship 2 cruisers 1 destroyer
Casualties and losses
33,000 dead 100,000 prisoners one destroyer	10,000 dead one battleship

TheWar in the North (Spanish:Ofensiva del Norte) was atheatre of theSpanish Civil War that occurred innorthern Spain from 31 March to 21 October 1937.

TheNationalists launched a number of offensives into parts of theBasque Country,Santander (Cantabria), andAsturias that formed anenclave loyal to theRepublican government. TheBiscay Campaign from March to July saw thebombing of Guernica andDurango and resulted in the Republicans losing the Basque Country after theBattle of Bilbao. The Nationalists captured Santander in September after theBattle of Santander and launched theAsturias Offensive against the last northern Republican stronghold in eastern Asturias. TheBattle of El Mazucu saw fierce Republican resistance against Nationalist attacks and possibly the first use ofcarpet bombing against a military target. The War in the North ended when the Nationalists broke through the Republican lines and captured the city ofGijón at the end of October.

In July 1936, upon theNationalist takeover ofNavarre, their leader GeneralEmilio Mola had announced awar of annihilation against theSecond Spanish Republic and no mercy to anydissent.^[3] Harsh repression started to be implemented against those blacklisted, who were Navarrese individuals and their families. By late August, theRequeté, a pro-NationalistCarlist militia from Navarre, advanced towardsIrun in theBasque Country with a mission to cut off Republican forces inGipuzkoa from theFrance–Spain border.^[4] In September, after thefall of Irun and then ofSan Sebastián, the Nationalists led byFrancisco Franco launched acampaign in Gipuzkoa and cut off the Republican-controlled areas in northern Spain from the border with France. That area had been already isolated from the rest of Spain by Nationalist control at the beginning of the war.

Northern Spain was very attractive to the Nationalists because of the industrial production ofBiscay and the mineral resources ofAsturias. Control of the area would be profitable because of its valuable resources and it could force atwo-front war. The resources ofiron,coal,steel and chemicals were a tempting target. Furthermore, its major supplies came by sea, which was controlled by the Nationalist navy. The north being such a heavily industrialised region made it a stronghold forfar-left politics and therefore the Republic. However, the northern Republicans were also politically divided and weakened by struggles between leftists andBasque nationalists, who mostly supported the Republic across the political sprectrum due to better chances for Basqueautonomy. Franco realised that the capitalMadrid was not going to be conquered quickly after a number of Nationalist offensives on the city and the surrounding area had failed. Franco ordered his commanders on the Madrid front to go on the defensive and to send all available resources to the north.^[5] Republican forces attempted to establish a front atBuruntza. Eventually, the front stabilised temporarily on the western fringes of Gipuzkoa (Intxorta) in October 1936, when theBasque Statute of Autonomy was passed in Madrid, and theBasque government was rapidly organised. As the Nationalists advanced, tens of thousands of panicking civilians from the occupied areas fled towardsBilbao.^[4]

On 31 March 1937, the Nationalists began a campaign to capture the province ofBiscay in the Basque Country with 50,000 men of the 61st Solchaga against theSpanish Republican Army's Army of the North commanded by GeneralFrancisco Llano de la Encomienda.^[6][7] The same day of the Nationalist offensive, theLegión Condorbombed the town of Durango with 250 civilian deaths. The Navarrese troops attacked the town ofOchandiano, and on 4 April, occupied it only after heavy combat. Mola then decided to stop the advance because of bad weather.^[8] On 6 April, the Nationalist government inBurgos announced theblockade of the Basque ports, but some British ships entered Bilbao. On April 20, the Nationalists continued their offensive and occupiedElgeta after a heavyartillery bombardment. The same day, theLegion Condorbombed the town of Guernica. The Basques retreated toBilbao's Iron Ring, and on 30 April, the ItalianCorps of Volunteer Troops occupiedBermeo, but the Nationalist battleshipEspaña was sunk by a mine.^[9]

The Republican government decided to send 50 aircraft of theSpanish Republican Air Force to Bilbao and launched theHuesca Offensive and theSegovia Offensive to stop the Nationalist advance, but both failed. On 3 June, Mola was killed in anairplane crash and replaced byFidel Davila. On 12 June, theBattle of Bilbao began when the Nationalists started their assault of the Iron Ring and, after heavy aerial and artillery bombings, they entered the city on 19 June, completing their conquest of the Biscay and the Basque Country.^[10]

After the fall of Bilbao, the Republican government decided to launch an offensive againstBrunete on 6 July to stop the Nationalist offensive in the north, but the offensive had ended by 25 July. The Republican troops inSantander Province (Cantabria) had low morale, though the Basque soldiers did not want to stop fighting. On 14 August, the Nationalists launched their offensive against Cantabria, with the 90,000 men (25,000 of whom were Italian) and 200 aircraft of the Army of the North. On 17 August, the Italians occupied theEl Escudo Pass and encircled 22 Republicanbattalions atCampoo. On 24 August, the Basque troops surrendered to the Italians atSantoña, which led to theSantoña Agreement, and the Republican troops fled from Santander. On 26 August, the Italians occupied the city ofSantander, and by 1 September, the Nationalists had occupied almost all of Cantabria. The Nationalists captured 60,000 prisoners, the greatest number during the war.^[11]

The Nationalists decided to continue their offensive intoAsturias after the failed Republicanoffensive against Zaragoza. Eastern Asturias was a Republican stronghold and the last piece of Republican-held territory in the north. The Nationalists had overwhelming numerical and material superiority, with 90,000 men against 45,000 and more than 200 aircraft against 35, but the Republican Army in Asturias was better organised than in Santander and the difficult mountainous terrain would provide excellent defensive positions. TheBattle of El Mazuco saw 30,000 Navarrese troops led by Solchaga and supported by theLegion Condor try to break through into eastern Asturias. This involved the widespread use ofcarpet bombing against Republican positions, in possibly one of its first uses against military targets in warfare. TheEl Mazuco valley and the critical nearby mountains (Peña Blanca and Pico Turbina), which were held by 5,000 Republican soldiers, fell to the Nationalists only after 33 days of bloody combat.^[12][13]

On 14 October, the Nationalists broke the Republican front and, on October 17, the Republican government ordered the evacuation of Asturias to begin. However, Nationalist ships were blockading the Asturian ports, and only the few military commandersAdolfo Prada,Francisco Galán, andBelarmino Tomas managed to escape. By 21 October, the Nationalists had occupiedGijón and completed the conquest of the northern zone.^[14]

With the conquest of northern Spain, the Nationalists controlled 36% of Spanish industrial production, 60% of the coal production and all of the steel production. Furthermore, more than 100,000 Republicanprisoners of war were forced to join the Nationalist army or were sent tolabour battalions.^[15] The Republic had lost the Army of the North (more than 200,000 soldiers), and by then, a complete military victory of the Republic in the war became impossible. Franco then decided to start a new offensive against Madrid, butVicente Rojo Lluch, the leader of the Republican Army, launched a diversionary offensive inAragon, resulting in theBattle of Teruel.^[16]

• List of Spanish Nationalist military equipment of the Spanish Civil War
• Condor Legion
• List of weapons of the Corpo Truppe Volontarie
• List of Spanish Republican military equipment of the Spanish Civil War
• Kasilda Hernáez

• Beevor, Antony (2006).The Battle for Spain: The Spanish Civil War 1936-1939. Penguin.ISBN 978-0-14-303765-1.
• Graham, Helen. (2005).The Spanish Civil War. A Very Short introduction. Oxford University Press.ISBN 978-0-19-280377-1.
• Jackson, Gabriel. (1967)The Spanish Republic and the Civil War, 1931–1939. Princeton University Press. Princeton.ISBN 978-0-691-00757-1.
• Preston, Paul (2013).The Spanish Holocaust: Inquisition and Extermination in Twentieth-Century Spain. London, UK: HarperCollins.ISBN 978-0-00-638695-7.
• Thomas, Hugh (2001).The Spanish Civil War. Penguin Books, Limited (UK).ISBN 978-0-14-101161-5.

• Juan Antonio de Blas,El Mazuco (La defensa imposible), inLa guerra civil en Asturias, Ediciones Júcar, Gijón 1986 (pp369–383).
  • El Mazuco (the impossible defence) Translated from the Spanish
• La Guerra Civil en Cantabria
• Almirante Cervera log

• Battles of the Spanish Civil War
• Conflicts in 1937
• 1937 in Spain
• 1937 in the Basque Country (autonomous community)

• Articles with short description
• Short description matches Wikidata
• Articles containing Spanish-language text