Jerusalem in Rome: New Light on the Façade Mosaics of Gregory IX (1227–41) and Passion Relics in Old St. Peter’s

Abstract

Cladding the front of the most important pilgrimage site of Western Christendom, the mosaic commissioned by Pope Gregory IX (1227–41) for the façade of Old St. Peter’s has received extraordinary scholarly attention, and yet its original appearance, meaning, and message have remained elusive. The identification of overlooked medieval sources, combined with a fresh reading of the known ones (both written and visual), suggests a new interpretation of this mosaic, together with the framing of its message in a broader context of transformation within the Roman Church and of changing relationships between Rome, Constantinople, and the Holy Land. Instead of focusing on relics of saints, images, or monuments—as in traditional readings—I offer a new approach to the basilica of St. Peter’s: a reappraisal of its inner space that calls attention to a hitherto neglected display of material objects that articulated a rich discourse on compunction, contrition, and penance through the exemplars of Peter and Judas as his antithesis. It becomes clear that, in his own basilica, Peter was not only presented as the first pope and the very foundational stone of the Roman Church but also as a sinner and a model of repentance and salvation. The discussion is then expanded to unveil new attitudes to pilgrimage and Passion devotion that enhance our understanding of the mosaic and the changes to the interior of the basilica, as well as their significance within the broader cultural, political, and spiritual context of that time. Gregory IX’s mosaic emerges as an extraordinary manifesto of his ecclesiology, his eschatological thought, and his perceived pastoral role, thus shedding new light on significant shifts in artistic narratives, papal self-fashioning, and societal attitudes in the second quarter of the thirteenth century.