At the end of the second century AD four small rooms were installed in the north-east corner of the Courtyard of Dionysus. In room A brick columns of a republican domus were reused. Room B could be entered from the courtyard. In room D is the black-and-white mosaic that gave the building its name. In the four corners are Dionysiac figures. In the centre is the young Dionysus, in a chariot drawn by tigers.