The preparatory materials for the novel Demons, published in the first academic edition of Complete Works by Dostoevsky contain his notes stating that the image of one of his main characters, Pyotr Verkhovensky, was partly stylized after M. V. Petrashevsky. At the same time, commentators found a note in this publication indirectly confirming the hypothesis that Nikolai Speshnev was one of the main prototypes of Stavrogin. The paper analyzes the preparatory materials for Demons, in which the future Stavrogin was listed as “Prince”. They are compared with Dostoevsky’s personal impressions of communicating with Speshnev, not only in 1847-1849, but also in the 1860s, after his return from exile. In addition, they are juxtaposed with printed materials about Petrashevsky and Speshnev’s stay in Irkutsk in 1857-1860. These comparisons demonstrate that significant elements of Demons’ creative history are related to the fact that while Petrashevsky took a noticeable part in the incident around the so-called “Irkutsk du