This paper is part of the D9 project (The Vatican and the Legitimization of the Physical Violence, Case Study of the Spanish Civil War) of the Cluster of excellence ‘Religion and Politics’ at the University of Münster. The bases of this study are the sources of the Vatican Archives. An analysis of how Pius XI made his official statement with regard to the standpoint of the Church in the Spanish Civil War on the 14th September 1936 has already been carried out (Zamagni 2013, Friede, Martyrium, Christenheit). A short synopsis of his statement is given in order to understand the difference of reasoning of the legitimization of the Spanish Civil War by the Spanish Bishops. This paper proves that the Holy See’s argumentation of the ‘Just War Theory’ was not taken into consideration by the Spanish Clergy. The legitimization of the war was provided by the bishops through the doctrine of the tyrannicide. Conclusively, in the common interest of supporting General Franco’s upheaval against the Republic, the Spanish bishops deemed a change of discoursive strategy as necessary in justifying the war.