This article delves into the passionate world of the conspiracies that led to the attempted coup d'état of 18 July 1936, the prelude to the bloody civil war of the following three years and the lengthy dictatorship of General Franco. Based on unpublished material of exceptional value from the personal archive of General José Sanjurjo Sacanell, the picture which emerges is of a process ruled by contingency. Nothing was decided beforehand, so decision-making was characterized by improvisation, doubts, frustrations, uncertainty and the constantly shifting positions of the principal actors. As a result, the plan to overthrow the Popular Front government and republican democracy was frequently on the verge of collapse.