The article reports on three illuminated incunabula, two of them currently held in the Biblioteca Angelica in Rome (Inc. 109, Inc. 530), and one in the Bancroft Library (Berkeley University, California, I I 8. V3 J35 1478p). The stylistic analysis of the illuminations and the study of other historical evidence – such as possession notes and coats of arms – allow to propose a new attribution of the illustrations, to precise where they were made, and to discuss the ancient history of the three books. The two incunabula of the Biblioteca Angelica were made by Ferrarese illuminators working in Urbino for Federico da Montefeltro in strict connection with his scriptorium, while the Bancroft one was produced by the Urbinate scriptorium only. The most outstanding of these three books, Inc. 530, Plinio's Naturalis historia in the Italian translation by Cristoforo Landino, presents an illuminated initial by Guglielmo Giraldi or a collaborator and a frieze by the Maestro del Curzio Rufo urbinate. The decoration made by artists usually working in illuminated manuscripts, not only in this incunabulum but also in the other discussed cases, reaffirms the strong connection between the world of the illuminated manuscripts and the first attempts to decorate and illustrate the first printed books.