He is best known as leader of the coup against the government of Juan Negrín; its objectives were preventing a Communist takeover and terminating fratricidal bloodshed during the war, considered already lost.

Himself he claimed - and this information is reproduced by the Spanish Real Academia de la Historia - that his parents, Tomás Casado Arribas and Tomasa López Quinsano, were farmers, and that his father worked as bracero.

[1] According to his own account during childhood and youth he suffered misery and it was thanks to extraordinary efforts of his parents that he managed to complete education in a local primary school.

According to some sources, at the time Casado became one of key advocates of armored units, up to total replacement of cavalry with arma blindada.

[12] In October 1936 he was recalled to Madrid and assumed the role of head of the operations department at the General Staff, reportedly because he was considered an “excellent planner”; he was also promoted to teniente coronel.

Following the decision to build mixed brigades he was active raising those units, though instead of the original concept of autonomous operations, he preferred them to be part of divisions.

[14] On March 5, 1939, the plotters declared the constitution of the Consejo Nacional de Defensa (CND), which claimed all power in the Republican zone; it was presented as a pre-emptive strike against an imminent dictatorial Communist takeover.

He temporarily acted as the CND president, but ceded the post to general Miaja the following day and within the body he assumed office as counselor of defence.

Once CND assumed full control over the Republic, Casado took part in some juridical proceedings, resulting in death sentences and execution of some Communist leaders, including Luis Barceló.

He intended to negotiate a staged surrender, evacuation of all those willing to leave Spain, with the added proviso of no political repression afterwards; he might have even hoped for re-integration of professional Republican officers into the post-war army.

He received a stipend from the British Committee for Refugees from Spain; following intervention of the Foreign Office, his allowances were set at a higher rate than normally.

In late 1939 he was given a job in the Spanish section of the BBC; he commented on military issues using the pseudonym of "Coronel Juan de Padilla".

[18] According to some scholars, BBC World Service served as a sort of a repository for individuals that British Intelligence thought potentially useful in the future.

To address ongoing financial problems, in 1967 he re-published The Last Days, in Spanish titled Así cayó Madrid; first serialised in a Falange periodical El Pueblo, it was then issued as a book.

In unclear circumstances the family got separated upon Casado leaving Spain in 1939; his wife and children remained in the country and initially sought refuge in the diplomatic legation of Panama.

Like Segismundo, he also became a professional cavalry officer and both brothers progressed almost simultaneously through the military promotion ladder, e.g. in 1913 both were segundos tenientes,[31] in 1923-1924 both were capitanes,[32] and in 1936 both were comandantes.

In his publications and in his private correspondence he used to refer to his childhood, spent in the misery and poverty of the rural working class, which reportedly made him sensitive to social injustice.

Though he did not engage in open politics, he must have been considered a loyal republican officer as, in 1935, he was nominated to the position of commander of the personal guard of the president, even though at the time the Right was in power.

There is no doubt as to his loyalty to the Republic following the coup d'état of July 1936, which was far more than simple “lealtad geográfica” of many professional officers trapped in the Republican zone.

Some scholars claim that in late 1936 he developed a particular knack against the Communists, as he blamed them for his sidetracking from General Staff operations towards other organisational work; he is presented as a man “eaten up with resentment”, though on personal rather than political grounds.

In his own papers and in some historiographic literature, Casado is pictured as a man of decisively progressive outlook, determined to fight for democracy, liberty and social justice against any sort of dictatorship – be it a Communist or a Francoist one.

[45] Casado's Asi cayo Madrid was rather well received by critics; reviewers presented the book as defense against absurd Communist charges of surrendering the Republic “cuando el pueblo quería continuar la lucha”.

[50] The advent of social and digital media produced an array of opinions, from those lambasting Casado as traitor[51] to these counting him among the heroes and great patriots,[52] as well as other voices in-between.

[53] In historiography the coup was increasingly viewed, not as an act to stop further killing, but as an avoidable error which facilitated the triumph of a Francoist dictatorship.

[55] In 2018 author Pedro López Ortega published a book that advanced the opposite view: Casado “represented realism and humanitarian sensitivity against folly and fanaticism of the others”.

[56] In his native town of Nava de la Asunción, until recently there was a minor street named after Casado,[57] but it was renamed and currently in Spain there is none.

In 1976 José María Rodríguez Méndez wrote Ultima batalla en El Pardo, a theatrical drama centred on the 1939 coup; its protagonists were Franco and Casado.

The work deals with the question of an individual facing great events and does not appear to take sides;[58] it was not published until the 1990s and in the 21st century made it to stage.