The Mithraeum Aldobrandini was excavated in 1924 by G. Calza on the premises of G. Aldobrandini. It was found 150 metres to the north of the Porta Romana on property owned by the Aldobrandini-family, and is still not accessible to the public. The south part of the shrine was not excavated. The back wall (north wall) was set against a tower belonging to the city wall from the first century BC. The tower was built with large tufa blocks. The east wall was set against the city wall (opus quasi reticulatum). The shrine was built in opus latericium, and has been dated to the late second century AD.