A discovery at Hadrian's Villa, a major archeological complex and UNESCO World Heritage site located just outside Tivoli, throws new insight on ancient Rome's religious traditions. A rare inscription associated with the fulgur conditum, the Roman ritual by which they consecrated locations struck by lightning, has been discovered in the vicinity of the "Amphitheater" by archeologists from the University of Urbino, in collaboration with the Istituto Villa Adriana and Villa d'Este. The discovery is noteworthy because the marble slab, intact in its original place, is situated within a small quadrangular structure that may designate a bidental, a sacred space designed to preserve the remnants of the event, which was regarded a direct manifestation of the divine. The completely readable inscription reads: FVLGVR SVBMANIVM, indicating a nighttime lightning strike attributed to Summanus, the Roman deity connected with lightning who strikes after sunset. Ancient accounts distinguished between these phenomena and daytime ones, which were attributed to Jupiter. For the Romans, a lightning strike transformed the struck area into a sacred and inviolable territory. The event-related material remains were collected, buried, and accompanied by special religious ceremonies. The fulgur conditum refers specifically to this procedure. The discovery, located between the Amphitheater and the tuff bank, provides new insights into the evolution of Emperor Hadrian's house. Archeologists believe that the interaction between the ritual site and the surrounding monumental structures can aid in reconstructing the area's alterations as well as the function religion had in the villa's spatial organization.