In order to define the concept of intrahistoria that he expounded in En torno al casticismo, Unamuno draws on "all his readings." Particulary important for him is the apprenticeship derived from some works by Galdos and from texts of Krausist affiliation, especially the ones by Francisco Giner de los Rios. This article examines these analogies from a philological perspective, and shows that the notion of intrahistoria was born in an incipient way in the first series of Episodios nacionales and, subsequently, is humanized as an idea thanks to the teaching of Giner de los Rios.