Building work to restructure the hospital of the Addolorata on the Caelian hill revealed the substantial remains of a residential structure of the mid-Imperial period. On this site stood the domus of the Valerii, an important aristocratic family whose origins went back to the early Republican period. The luxurious residence, which already existed in the late Republican period, was in use until the beginning of the 5th century A.D. Earlier excavations had brought to light evidence of the late Republican and late antique phases but no evidence for the intervening phases. The excavation undertaken in 2005 revealed a section of a large, frescoed corridor that was paved with a black and white mosaic and had windows opening onto a viridarium. It was structured in such a way as to re-use, in the mid Imperial period, spaces that had been defined in the time of Augustus. However, it was soon abandoned and in the first quarter of the 3rd century A.D. was destroyed when the ceiling and upper part of the walls were intentionally demolished. Above the collapses lay a dump of high quality painted plaster and decorative stucco datable to between the 1st and beginning of the 2nd century A.D., material which came from a different part of the domus. The structure was completely obliterated, within the 3rd century A.D., by the insertion of a basement room which was probably built as part of the restructuring which involved changes to the terracing on which the domus was constructed. Due to the particular way in which the structure collapsed the room’s interior decoration was recovered and in the future will be reconstructed almost in its entirety. Following the robbing and abandonment of the structures, but before they were obliterated, the area of the viridarium was used for dumping rubble. In this period, this part of the domus was struck by lightening, an event attested by the bidental found up against the boundary wall of the garden. (Sergio Palladino- Claudia Paterna)