The siege of the Montaña barracks () was the two-day siege which marked the initial failure of the July 1936 uprising against the Second Spanish Republic in Madrid, on 18–20 July 1936, at the start of the Spanish Civil War. The bulk of the security forces in Madrid remained loyal to the government, and supported by workers' militias, crushed the uprising. Background On 17–18 July 1936, a part of the Spanish army, led by a group of officers—among them Generals Jose Sanjurjo, Francisco Franco, Emilio Mola, Manuel Goded and Gonzalo Queipo de Llano—tried to overthrow the Popular Front government of the Second Spanish Republic. The occupation of the capital, Madrid, was one of the prime goals of the coup of July 1936. This coup in this particular location was ill-planned and clumsily executed. There was no coordination between the diverse elements who were hostile to the republic – falangists, monarchists, some army officers, and members of the Spanish Military Union. The coordinator of the plot in Madrid, Colonel Valentín Galarza Morante had been detained and the elderly and indecisive General Villegas took his place. However Villegas decided at the last minute to avoid direct participation and General Joaquín Fanjul replaced him at short notice. There was a particularly strong concentration of pro-government forces in Madrid. These included para-military security forces and organized—though at this stage generally unarmed—union groups. Finally, a large portion of the officers and soldiers of the regular Madrid army garrison were uninvolved in the plot and pre-disposed to remain loyal to the elected government. Located on the Príncipe Pío near the former Royal Palace of Madrid to the west of the central city, the Montaña barracks had been built in 1860. It consisted of three separate buildings joined to make up a large fortress-like structure, fronted by a wide glacis and parapets. It was normally garrisoned by three regiments of infantry, a regiment of engineers and additional specialist units, although in July 1936 many of the soldiers were on summer leave. A further eight regiments, plus four independent battalions and two artillery groups, were based in other garrisons located in and around the city. Finally, 25 companies of Assault Guards and 14 of Civil Guards were either located in Madrid or had been brought in by the Republican authorities shortly before the July rising. The role of these trained security forces was to prove crucial. The coup