Madrid was the scene of the greatest battle of the Spanish Civil War, a war that weighed on all international political and diplomatic life for three years, drew the attention of the whole world to the extremist policies of fascism and communism, and turned out to be, in many ways, an anticipation of the Second World War. The conquest of Madrid was not a military necessity, but it was obvious that those who would control the Spanish capital would pass in the eyes of the Spanish people and foreign countries for the representatives of the real governmental authority of the country. As long as Madrid remained in Republican hands, the Nationalists could not hope to be officially recognized as the legitimate holders of power.
The 28th government of the country in five years came to power in the general elections of 1936. The Popular Front (Frente Popular), a coalition of left-wing parties, was elected in an extremely tense social climate:political struggles and murders, attacks on seats of political parties and newspapers, strikes. It was to "fall" in an even more dramatic way than its predecessors. Activist political organizations (anarchists and communists, fascists and monarchists) rose up against the Republic and its government, arming themselves in secret and multiplying acts of violence with a view to overthrowing the constitutional government. As early as July 1936, several groups plotted to seize power and establish a state based on their particular interests and ideologies.
The monarchist organization, Spanish Military Union (U.M.E.), was the most dangerous of these clandestine movements. Formed in 1931 by a “secret group” of officers, it wanted to establish order and discipline through a military dictatorship. In the meantime, she worked to create a "revolutionary climate in the army".