Battle of Guadalajara The Battle of Guadalajara ( March 8 – 23 , 1937 ) saw the Republican People ' s Army ( " Ejército Popular Republicano " , or EPR ) defeat Italian and Nationalist forces attempting to encircle Madrid during the Spanish Civil War . The Nationalist forces involved in the Battle of Guadalajara were primarily the Italian Corps of Volunteer Troops ( " Corpo Truppe Volontarie " , or CTV ) . The battle opened with an Italian offensive on 8 March . This offensive was halted by 11 March . Between 12 March and 14 March , renewed Italian attacks were supported by Spanish Nationalist units . These were halted too . On 15 March , a Republican counter - offensive was prepared . The Republicans successfully launched their counter - offensive from 18 March to 23 March . Preceding activities . After the collapse of the third offensive on Madrid , Spanish Nationalist General Francisco Franco decided to continue with a fourth offensive aimed at closing the pincer around the capital . The Nationalist forces , although victorious at Jarama River , were exhausted and could not create the necessary momentum to carry the operation through . However , the Italians were optimistic after the capture of Málaga , and it was thought that the Italian forces could score an easy victory owing to the heavy losses sustained by the Republican army during the Battle of the Jarama River . Italian dictator Benito Mussolini endorsed the operation and committed the Italian units to it . The Italian commander , General Mario Roatta , planned that his forces would surround the defences of Madrid from the north - west . After joining the Spanish Nationalist corps " Madrid " on Jarama River , they would begin the assault on Madrid . The Italian forces would execute the main attack . The Spanish division " Soria " was present to secure the operation , but played no part in the first five days of fighting . The main attack began in the 25 km - wide pass at Guadalajara - Alcalá de Henares . This region was well suited for an advance , as there were five roads of high quality running through it . Three other roads in the area led to Guadalajara , allowing for the possibility of capturing this town as well . The Nationalist forces had 35 , 000 soldiers , 222 cannon , 108 L3 / 33 tankettes and L3 / 35 tankette s , 32 armoured car s , 3 , 685 cars , and 60 Fiat CR . 32 fighter planes . The Italian tankettes and armored cars were organized as the " Tank and Armoured Cars Group " ( " Agrupación de carros de asalto y autos blindados " ) . The Italian aircraft were organized into the " Legionary Air Force " ( " Aviazione Legionaria " ) . The Republican presence in the Guadalajara region consisted only of the 12th Division of the Spanish Popular Army under Colonel Lacalle . He had under his command 10 , 000 soldiers with only 5 , 900 rifles , 85 machine guns , and 15 cannon . One company of light tanks were also sent to the area . No military engineering works had been effected in the Guadalajara region , because it was regarded as a peaceful part of the front . The Republican Army staff was sure that the next Fascist offensive would come from the south . Italian offensive . March 8 . After 30 minutes ' artillery fire and air raids on the Republican positions , the Italians began advancing upon the 50th Republican brigade . Led by tankettes , they broke through the Republican line . Their assault then slowed down , mainly because fog and sleet had reduced visibility down to in places . The Italians captured between 10 and 12 km of terrain , including the towns of Mirabueno , Alaminos and Castejon . Falling back , the Republican commander requested infantry reinforcements and the company of tanks . March 9 . The Italians continued their assault on Republican positions . The main attack was carried out with tanks , but was again bogged down by poor performance and low visibility . The Republican 50th Brigade escaped without a fight . At about noon , the Italian advance was suddenly turned back by battalions of the XI International Brigade ( battalions involved were Edgar André Battalion , Thälmann Battalion and Commune de Paris Battalion – with soldiers mainly from Germany , France , and the Balkan countries ) . The Italians had taken another 15 to 18 km of terrain and the towns of Almadrones , Cogollor , Masegoso . In the evening , the first formations of Italian troops reached the suburb of Brihuega , where they settled down to await a widened breach in the Republican lines . This break in momentum , though incompatible with the " blitzkrieg " tactics they were nominally following , was under the circumstances necessary to allow the soldiers to rest . The Republican forces on this day consisted of the XI International Brigade , two artillery batteries and two companies of infantry from the 49th Brigade , 12th Division . They had 1 , 850 soldiers with 1 , 600 rifles , 34 machine rifles , 6 cannons , and 5 tanks . By the end of the day , more reinforcements started to arrive as Colonel Enrique Jurado was ordered to form IV Corps with Líster ' s 11 Division in the centre at the Madrid – Zaragoza road at Torija , 12th Division on the left flank and 14th Division on the right . March 10 . The Republican forces received new reinforcements : XII International Brigade ( two battalions ; Jarosław Dabrowski Battalion and Giuseppe Garibaldi Battalion ) , three batteries of artillery , and an understrength battalion of tanks . The Republican forces now had 4 , 350 soldiers , 8 mortars , 16 cannon and 26 light tanks . In the morning Italian forces launched heavy artillery and air bombardments and began the assault on the XI International Brigade without success . At that point they had 26 , 000 soldiers , 900 machine guns , 130 light tanks and a large number of cannon committed to battle . The Nationalists captured the towns Miralrio and Brihuega . The latter town was taken almost unopposed . Italian attacks on XI and XII International Brigades continued throughout the afternoon , still without success . At Torija , they met the Italian Garibaldi Battalion . During the skirmish the Italians from the Garibaldi Battalion took the opportunity to encourage the Fascist soldiers to join the Republicans . The attacks were halted towards evening , and the Italian Nationalist units built defensive positions . At the end of the day , Lacalle resigned his command , officially for health reasons , but probably because of his resentment over being passed over by Jurado . Command over 12th Division was given to the Italian communist Nino Nanetti . March 11 . The Italians began a successful advance on the positions of XI and XII International Brigades , who were forced to retreat down the main road . The Italian vanguard was stopped some 3 km before the town of Torija . The Spanish Nationalist division " Soria " captured the towns of Hita and Torre del Burgo . Republican counterattacks . March 12 . The Republican forces under Líster ' s command redeployed in the morning and launched a counterattack at noon . Close to one - hundred ' " Chato " and " Rata fighter planes and two squadrons of Katiuska bombers of the Spanish Republican Air Force had been made available at the Albacete airfield . While the aircraft of the Italian Legionary Air Force were grounded on water - logged airports , the Republicans did not have this problem since the Albacete airfield had a concrete strip . After an air bombardment of the Italian positions , the Republican infantry supported by T - 26 and BT - 5 light tanks attacked the Italian lines . Several Italian tankettes were lost when General Roatta attempted to change the position of his motorized units in the muddy terrain ; many got stuck and were easy target for strafing fighters . The advance reached Trijueque . An Italian counterattack did not regain lost terrain . March 13 . The Republican counterattack on Trijueque and Casa del Cabo , Palacio de Ibarra was launched with some success . The plan was to concentrate 11th Division under Líster and all armoured units on the Zaragoza road , while 14th Division under Mera crossed the Tajuña River to attack Brihuega . The Italians were warned that this might happen , but ignored advice from the Spanish chief of operations , Colonel Barroso . Mera nearly failed to cross the river , but local CNT members advised him where to place a pontoon bridge . March 14 – 17 . On March 14 , most Republican infantry formations rested while their airforces executed successful attacks . The International Brigade captured the " Palacio de Ibarra " . In the subsequent days the Republicans redeployed and concentrated their forces . The Republican forces now consisted of some 20 , 000 soldiers , 17 mortars , 28 cannon , 60 light tanks and 70 planes . The Italian and Spanish Nationalist forces consisted of some 45 , 000 soldiers , 70 mortars , 200 cannon , 80 light tanks ( L3 tankettes ) , and 50 planes . March 18 . At dawn , Mera led 14th Division across the pontoon bridge over the Tajuña River . They had cover from heavy sleet , but the weather also delayed the assault . After midday , the weather had improved enough to allow the Republican air force to operate . At around 13 : 30 , Jurado gave the order to attack . Líster was slowed down by the Italian Littorio Division , arguably the best of the Italian units . 14th Division nearly managed to surround Brihuega , and the Italians retreated in panic . Remaining Italian soldiers were cleared out by the XI International Brigade . An Italian counterattack on Republican positions failed . The Littorio Division saved the Italians from a complete disaster when they conducted a well - organized retreat . March 19 – 23 . The Republican forces recaptured the cities of Gajanejos and Villaviciosa de Tajuña . Their counter - offensive was ultimately halted on the Valdearenas – Ledanca – Hontanares line , because Franco had sent reserve formations to settle the line of defence between Ledanca and Hontanares . Aftermath . The Battle of Guadalajara was the last major victory of the Republican Army and did much to lift morale . Herbert Matthews claimed in the " New York Times " that Guadalajara was " to Fascism what the defeat at Bailén had been to Napoleon . " The British press heaped scorn on this " new Caporetto " — alluding to a great Italian defeat in the First World War — while former British prime minister David Lloyd George wrote mockingly of the " Italian skedaddle , " infuriating Mussolini . The Italian CTV lost some 6 , 000 men ( Spanish Nationalist losses were marginal ) and a considerable number of light tanks and planes . In addition , the Republican army captured sizeable quantities of badly - needed matériel and equipment , including 35 artillery pieces , 85 machine gun s , and 67 vehicles . Strategically , the Republican victory prevented the encirclement of Madrid , ending Franco ' s hopes of crushing the Republic with a decisive strike at its capital . Franco decided to adopt a new strategy of chipping away at the Republican territories , starting in the north . Above all , Guadalajara was a severe blow to Italian morale and a loss of prestige for Italy ' s fascist regime , whose " Duce " had orchestrated the deployment of the Italian army in the hopes of stunning the world with a show of Italy ' s " iron military strength . " The disappointing performance of Italian arms reached its nadir at Guadalajara . In response , Franco announced his intention to dismantle the Italian field army in Spain , seeking to disperse it among Spanish Nationalist units . This threat was not ultimately carried out and Guadalajara in a sense guaranteed continued Italian aid as Mussolini sought final victory to efface his humiliation at Guadalajara . If Republican confidence soared , there was no corresponding loss of morale in Nationalist circles , which regarded the Italian expeditionary force with some contempt . German officers in Salamanca sneered that even " Jews " and " Communists " — as the International Brigades were stereotyped — could beat the Italians . Many Spanish Nationalist officers , resenting Mussolini ' s henchmen for carrying their own personal war into Spain , were amused to see their boasting and well - equipped allies , so full of bluster before entering battle , brought so low at the hands of fellow Spaniards , even enemy Spaniards . Franco ' s soldiers began singing popular Italian tunes with lyrical changes mocking the defeated CTV . The following chorus , originating with General Moscardó ' s Navarrese , humorously takes the Italians to task for their earlier complaints about the lack of motorized transport in Nationalist ranks : The CTV most likely lost the battle because Franco did not start a side offensive , from Jarama toward Alcalà de Henares , as agreed on March 1 with General Roatta . After seeing that the Nationalist was not attacking Republicans was able to redeploy the troops facing Jarama to meet the Italian offensive . Later , when faced by General Roatta , Franco tried to excuse himself saying that his Generals ignored his orders to advance . It is possible he used the Italian troops as cannon fodder to gain time to regroup his troops , exhausted after Jarama . ( Paul Preston - A Concise History of the Spanish Civil War ) Military significance . The tactical lessons of the battle were ambiguous and prone to misinterpretation . The failure of the Italian offensive demonstrated the vulnerability of massed armoured advances in unfavourable terrain and against a coherent infantry defence . The French General Staff , in harmony with existing beliefs in the French Army , concluded that mechanized troops were not the decisive element of modern warfare and continued to shape their military doctrine accordingly . A notable exception to this view was Charles de Gaulle . The Germans escaped this conclusion by correctly dismissing the Guadalajara failure as the product of Italian incompetence . In truth , both views had some merit : armoured forces were largely ineffective against prepared defences organized in depth ; in adverse weather , and without proper air support , the result was disaster ( Italian strategists failed to consider these variables ) . But the German assessment correctly noted the deficiencies in Italian soldiery , planning , and organization that contributed to their rout at Guadalajara . In particular , their vehicles and tanks had lacked the technical quality and their leaders the determination necessary to effect the violent breakthroughs characteristic of later German blitzkrieg tactics .