| Original caption: “Spanish loyalists charge up a hall near Somosierra, Spain, to wipe out a rebel machine gun nest. The Guadarama Mountains were the scene for firece battles between forces loyal to the government and rebels in the civil war.” The struggle for control of the chain north of Madrid comprising the Sierra de Gredos and the Sierra de Guadarrama was critical to controlling Madrid. This complex and wide system of mountains and twisting valleys often with steep sides is a formidable barrier from which the plains to the north and south can be controlled. As the terrain is so difficult, control of the few roads crossing the area forms the key to the pattern the battle assumed. The 2 main roads from the north were the main axes of advance and fierce fighting quickly developed round the Somosierra Pass on the Burgos-Madrid road, and the Alto del León on the Valladolid highway. Both these passes had been seized by militia forces rushed up from Madrid, but a column sent to take Avila, under Colonel Julio Mangada (June 30, 1877 – April 14, 1946), halted at Navalperal apparently because its commander did not fancy being at the end of a long and tenuous line of communication. When the column withdrew a serious potential threat to the1 rebel build-up was removed. Similar lapses of co-ordination by Republican Army commanders show how the lack of a really firm central military high command could turn possible victory into probable defeat. The pass through the mountains on the Burgos road is called Somosierra and was long recognized as a strategic stronghold against hostile forces. It was here, that the citizens of Madrid put up a stand against Napoleon’s army when it marched on the city in November, 1808. As soon as it became known that the Nationalist force was heading south in July 1936, militiamen from Madrid once again rushed to the somosierra pass. The Burgos road was a vital conduit to the city and, crucially, a nearby reservoir supplied Madrid with fresh water: had the reservoir fallen into Nationalist hands, taps in the capital would have run dry within days. As a popular destination for summer excursions, many Madrileños knew the sierra well, and initially holding the Nationalists there was done without significant casualties. Republican militiamen traveled easily between the city and the mountain pass, bringing reinforcements and supplies. The Nationalist Army, too, swelled in numbers as more troops arrived from Burgos. The battle intensified, and the 2 sides fought each other to a standstill. Frustrated by the failure to push through the Somosierra pass, rebel commanders rapidly looked for alternative routes over the mountains into Madrid. To the west, the road snaking its way through the Puerto de Guadarrama pass, above the mountain town of Guadarrama, was next on their list. The essential characteristic was the abundance of volunteers, the cover provided by Regions 5 (Aragon) and 7 (Valladolid), and the presence of an organizing Nationalist figure like General Emilio Mola y Vidal (July 9, 1887 – June 3, 1937), 1st in Pamplona and later in Burgos. These 3 favorable circumstances led to the early emergence of a significant number of Carlist Requeté units, well organized and with a certain offensive capacity. 4 columns were immediately launched. 2 of them from Pamplona, heading for Tolosa and Oyarzun. Another from Estella, heading for Alsasua. And the 4th from Vitoria to Villarreal. In these directions, Requeté forces and the restless Falange of Navarre and Alava made their 1st steps, receiving, with their baptism of fire, a suitable organization and training under the direction of experts in the field: professional soldiers. And so, in the months of August and September 1936, Navarre and Alava were secured and Guipúzcoa was occupied, closing the French border at Irún to the Republicans. But this did not exhaust the number of Navarrese Carlist troops in the ranks. With Francisco Garcían Escámez’s (March 1, 1893 – June 12, 1951) Column, Requetés departed for Somosierra, and others were sent to Alto del León, while Zaragoza and Huesca, under Republican threat, received aid from Navarrese Requetés in critical moments. The rebels’ reaction was to throw in every available man from the Avila and Segovia areas to block the enemy’s path so that time could be gained for bringing up regular forces from further back. The counter-attack began on July 19 with an attempt to outflank the eastern end of the mountain chain by a thrust aimed at Guadalajara via Logroño, Soria, and Sigüenza. General Mola sent Escámez with about a 1,000 Nationalist militia composed of a small unit regular army soldiers, requetés, and Falangists, south from Navarre towards Guadalajara. But they were unable to reach it – the 1st of many efforts to reach Madrid had failed. Garcia Escamez then circled round east to the Somosierra pass, almost due north of Madrid, to hold it for the Nationalists on July 25. At the same time, other Nationalist forces headed down from Valladolid to the Alto del Léon pass between Avilá and Segovia, which they took on July 22. Lack of ammunition, however, as well as determined Republican resistance, prevented these various columns under Mola’s ultimate command from getting any closer to Madrid. Republicans continued to hold the major pass between Somosierra and Alto del Léon, at Navacerrada, right to the end of the war. For a while the front stabilized. At some points the front line was only 40 miles (64 kilometers) north-west of the capital. But the column delayed at Logroño to ensure that the rather half-hearted support for the rising shown there was no real danger; the Madrid Republican militia thus won the race to Guadalajara. The rebel force was too small to clear them out so this key town covering the valley leading to Alcalá and Madrid was not secured. The column retraced its steps to the north of Sigüenza, swung west to Aranda de Duero, then turned south to reinforce the small group of rebels who had seized the Somosierra tunnel. It arrived at an opportune moment because Nationalist militia from Guadalajara were moving north to the same area. These troops fought with great ferocity, but blind courage not supported by adequate training and firepower was no match for regular soldiers, whose experience was combined with superior artillery. A similar situation arose at the Alto del León where the rebel attack had begun when a column under Colonel Ricardo Serrador Santés (1877 – January 23, 1943) arrived from Valladolid on July 22. The actual battle followed the Somosierra pattern but was shorter as the pass was under rebel control by the end of the same day. The result of the Sierra fighting was high losses for the Republicans, who, though they still held the crests of the mountains between, were now split by 2 small salients thrusting southwards down 2 of the main routes to Madrid from the north. On the other hand, they held Guadalajara, blocking any further thrust from the northeast. This early fighting was brave and brutal on both sides, setting a pattern that would continue in the long struggle for territorial domination. On both sides, too, the militias were vitally important. The Communists were soonest and best organized compared to the Republicans, with militia groups in Madrid swiftly being incorporated into the new Communist 5th Regiment, under leaders like Brigadier General Juan Modesto (September 24, 1906 – April 16, 1969), and Enrique Líster Forján (April 21, 1907 – December 8, 1994). But the existence of separate Anarchist, Socialist and Communist columns represented an enormous problem as well as a resource for the government. They were determined to retain their own political identity and autonomy, even at the front. The most revolutionary militias, the Anarchists and the Partido Obrero de Unificación Marxista (POUM – “Workers’ Party of Marxist Unification”), would not obey orders they disagreed with. Militias based on the various trade unions and left-wing parties were instinctively suspicious of Republican Army leaders, and often with good reason: for instance, General Luis Castelló, appointed Minister of War on July 19, fled to France early in August 1937 after anarchists shot his brother and Nationalist captured his wife and daughters when the city of Badajoz fell, and Nationalists massacred the Republicans there. His daughters survived. Apart from the action around Madrid, and in Aragón, local changes in military control occurred in several other places in late July. Rebel garrisons in San Sebastián and Valencia, which were enclaves in Republican areas, were overwhelmed. Republican militias from Valencia then advanced as far north as Teruel, the south-east extreme of rebel territory, though they failed to take it. The Nationalists also made some gains. In particular, General Queipo de Liano (February 5, 1875 – March 9, 1951) extended his control across the south-west corner of the country, linking the towns already in rebel hands by conquering the surrounding countryside. 2 weeks after the initial risings, the Republic was stronger in the east and north, the Nationalists in the southwest, but the overall balance of forces had not changed dramatically. It is difficult to grasp the significance of these nearly 13,000 Navarrese Carlist volunteers. Especially considering that the population of Navarre was 345,883 people. 1 in 3 Navarrese males of military age was at the front as a volunteer. Other Requeté formations were created in other parts of the 6th Organic Division, especially in Burgos and Palencia, dedicated, along with the Falangist volunteers and other forces, to garrisoning the front south of Santander. Navarre 1st, and then the other provinces of the Division, constituted what, over time, would become the basis of the National Army’s mass of maneuver. This would make it strong enough to win the Spanish Civil War. Along with the Navarrese on the northern fronts and in Somosierra, formations of Requetés from Alava and Rioja appeared, although in smaller numbers. From this early period, the great military valor exhibited by the Alava people was striking, their fame and skill continuing throughout the war. In October 1936, the total number of Nationalist combatants was 46,485 men. Of these, the number of volunteers was 30,177. This represents a 65 percent share of the total number of combatants. Of the 30,177 volunteers, 18,402 were Requetés, representing 61 percent of the total number of volunteers. Of the 18,402 Requetés, no fewer than 12,845 were Navarrese. Of these, 3,600 fought within the Division’s territory and 9,300 outside of it, in Guadalajara, Guadarrama, Mosierra, and Aragon. | |
| Image Filename | wwii0822.jpg |
| Image Size | 1.13 MB |
| Image Dimensions | 5000 x 3413 |
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| Photographer Title | |
| Caption Author | Written or Adapted by Jason McDonald |
| Date Photographed | August 12, 1936 |
| Location | |
| City | Somosierra |
| State or Province | Madrid |
| Country | Spain |
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| Record Number | |
| Status | Caption ©2026 MFA Productions LLC Please Do Not Duplicate or Distribute Without Permission; Image in the Public Domain |
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