In the seventeenth century, religious paintings entered Roman private galleries transforming into a movable repertory of motifs apt for re-elaboration through intertextual relationships with other artistic genres. The re-location and unorthodox arrangement of sacred paintings in the stanze dei quadri has been generally understood as a process resulting in their commodification. However, the creation of biblical representations specifically intended for the Galleria suggests that subject matter still retained an important function, although a radically different one. New Testament narratives now offered artists new opportunities to reinvent painting. The so-called Caravaggisti distinguished themselves for exploring these newly-opened paths by conflating sacred and profane subjects in their gallery paintings - such as those representing the Denial of St. Peter. By examining some of the numerous representations of this biblical narrative set in seventeenth-century Roman taverns, this article explores the overlooked visual and theoretical conception behind the creation of these complex images produced by a generation of painters that, so far, has been overshadowed by Caravaggio. The concept of denial will be pivotal to the re-assessment of the function of religious representations created for the Roman Galleria. The exploration of such representations, in turn, will be crucial for opening up widespread, yet still under-investigated concepts that underlie the making of what is now called Caravaggisti - particularly truth in painting, mimesis and the process of replication that still binds their works with the uncontested notion of Caravaggio as the original.