The Battle of Brunete (6–25 July 1937), fought 24 kilometres (15 mi) west of Madrid, was a Republican attempt to alleviate the pressure exerted by the Nationalists on the capital and on the north during the Spanish Civil War. Although initially successful, the Republicans were forced to retreat from Brunete after Nationalist counterattacks, and suffered devastating casualties from the battle.
After the capture of Bilbao by the Nationalists on June 19, the Republicans devised the attack on Brunete to divert Nationalist forces from the north and allow the fleeing Republicans time to reorganize. In addition, Brunete was also chosen because it was situated on the Extremadura road and its capture would make it harder for the Nationalists to resupply their forces besieging Madrid, defeat here perhaps even forcing the Nationalsts to withdraw. Once Brunete had been taken, and after some reorganization, the plan was that the offensive would then in a second phase continue in the direction of Talavera de la Reina, a move that would eventually cut off the Nationalist forces outside Madrid. At the same times as the offensive on Brunete started an enveloping attack would be launched from the Carabanchel area just south of Madrid.
From a political standpoint, the offensive was chosen for Brunete to satisfy communist demands and to prove to the Russians that the Spanish possessed military initiative. In fact, Russian advisors had been pressing for an attack on Brunete since the spring of 1937. Furthermore, assistance from the Soviet Union had decreased due to the successful blockade of Republican ports by the Nationalists. Prime Minister Juan Negrín needed to convince the French Premier Camille Chautemps that the Spanish Republic was still capable of military action after the disastrous losses of Málaga and Bilbao. It was expected by the Republicans that a show of force at Brunete would persuade France to open its border for arms shipments.
The Brunete offensive followed two previous Republican offensives, one at Huesca in Aragon, a second in the area of Segovia, northwest of Madrid, both of which had failed. Despite these setbacks, the Brunete offensive was the subject of significant planning by Soviet officials supporting the Republican military; in addition, it received significant combat resources, the Republicans deploying some 50,000 troops, including five of the International Brigades. Whether logistic planning for the attack matched planned combat operations remains a matter of historical contention.
The offensive had been preceded both by major reorganizations of the government's forces as well as an influx of modern war material, mainly from the Soviet Union. Nine new brigades had been set up, and the number of heavy machine guns in the units had been increased. The command control expertise demonstrated by Republican formation commanders, along with problems involving all-arms coordination (particularly Republican air support), would, however, cause significant issues. The offensive was meant as a surprise attack, and the Nationalists were indeed caught unaware – despite the fact that "it had been discussed in the cafés of the Republic for three months".
The terrain where the battle was to be fought is pretty hilly, with many ridges and small creeks, but for the most part open, and thus accessible to the Republicans new Soviet tanks, which they now intended to put to their first full use.
General Miaja initially commanded two Spanish Republican Army corps.
V Army Corps commanded by Colonel Juan Modesto with some 22,000 soldiers (among them five of the International Brigades) and 100 tanks:
11th Division, led by Enrique Líster.
35th Division, led by General Walter.
46th Division, led by El Campesino.
XVIII Army Corps commanded initially by Colonel Enrique Jurado and later by Segismundo Casado with some 20,000 men:
10th Division, led by Major José Maria Enciso.
15th Division, led by Colonel Janos "Gal" Galicz.
34th Division, led by Colonel Francisco Galán.
In reserve were Cipriano Mera's 14th Division, General Kléber's 45th Division, and Gustavo Duran's 69th Division. The reserve forces consisted of some 25,000 men and 40 tanks.
The site of the offensive was well chosen. Initially facing the Republican attack was not a continuous Nationalist line of defense but (as in many parts of Spain in the initial phase of the war) a series of outposts in villages, defended by small detachments able to take the terrain between the outposts under flanking fire. This part of the front was part of the Nationalist Army of the Center, under the command of General Andrés Saliquet Zumeta. However, pretty soon after the battle had started the overall command was shifted to General José Enrique Varela Iglesias. The units that fought during the battle were:
The VII Army Corps commanded by General José Varela consisted of: