The article studies the reflection of Carlist and ‘Liberal’ mythological concepts, formed in 1830s– 1890s in Spain, in the novel Zumalacárregui by Benito Pérez Galdós. There is given a brief overview of some previous research works concerning Galdós´s National Episodes and the novel Zumalacárregui. The paper focuses on the ways of representation of general Tomás de Zumalacárregui (1788–1835) in the novel and shows the processes of creating the myths related to the general. In the 19–20th centuries, Zumalacárregui became a hero for the representatives of three different ideologies: Carlism, Francoism, and Basque Nationalism. It is shown that mythologization of the general began just after his death in 1835. Based on the text of the novel, there are made conclusions concerning the sources that Galdós used when creating it. The writer studied the most relevant memoirs about the First Carlist War. The paper shows how Galdós’s text was influenced by the memoirs of A. Sabatier, Ch. F. Henningsen, F. von Lichnowsky, J. A. Zarátiegui, F. Fernández de Córdoba, and H. Du-Casse. It is also noted that Galdós could have been inspired by some pictures created in the traditions of ‘Carlist visual art’. It is concluded that the writer used both Carlist and ‘Liberal’ myths concerning Tomás de Zumalacárregui. The text of the novel is divided into two parts, ‘historical’ and ‘narrative’. The ‘historical part’, i. e. a general description of the First Carlist War military operations carried out in 1834–1835, is mainly based on Carlist sources. In this part, the general Zumalacárregui is described as a war hero. The ‘narrative part’ mainly refers to ‘Liberal’ sources. The author introduced in this part a fictional character, priest José Fago, being the general’s ‘double’. Through Fago’s moral doubts and hesitations Galdós showed the internal tension of Zumalacárregui.