This article describes the discovery of an area of habitation of the domus of the Valerii, a family with yen ancient origins, said to descend from the first consul, Valerius Publicola. The excavation, undertaken in 2005, investigated deposits beneath the Ospedale dell'Addolorata where, in the early years of the twentieth century, the construction of the southeast block destroyed the upper levels and a complex row of structures along the northern side, towards via Santo Stefano Rotondo. Since the middle of the sixteenth century, uncontrolled excavation and research have recovered an important inheritance of knowledge and of high-quality finds — often sold or dispersed in some way. The excavation has revealed part of a frescoed corridor, 3.8 m wide and originally c. 3 m high, with a pavement in black mosaic, with windows opening onto a garden. Of this imposing structrure, datable to the late Hadrianic period, various phases of building activity, abandonment and reuse have been identified, amongst which the construction of a hidental is of particular interest.