This paper aims to further explore the complex figure of Giusto Fiammingo, a painter active in Rome in the first half of the 17th century and associated with the Naturalist movement. Ever since Federico Zeri's famous 1959 attribution identifying him as the 'Master of the Pallavicini Angels', critics have long debated the identity of this enigmatic artist. Through an analysis of two previously unpublished documents and the proposal of new attributions to Joost de Pape, this study intends to provide an original contribution to the reconstruction of Giusto's artistic biography, suggesting a possible solution to the long-standing question of his true identity.