This essay analyzes the presence of the modern concept of melancholy in the Intercenales (1424-1439) by the humanist Leon Battista Alberti. The Intercenales is a collection of satirical, allegorical and moralizing writings composed with the purpose of entertaining an audience of close friends. In spite of the fact that the term "melancholia" does not appear in the text, this paper argues that Alberti's character of "the philosopher" is melancholic, since he is "ill in the soul" (suffering from morbus animi), and his illness is evidenced by a series of physical and psychological symptoms associated with melancholy in the classical and medieval medical traditions. These symptoms are stomach pain, pallor, insomnia, a rich memory, a propensity to study at night, and an ability to have premonitory dreams. With this characterization Alberti promotes a connection between melancholy and being a genius, which is distinctive to the Renaissance and the basis for the modern concept of melancholy. The essay concludes that the ultimate purpose of the Intercenales is to cure, from a literary and philosophical point of view, the illness of the melancholic philosopher.