This small building (c. 11 x 7 metres) is to the south-east of the Temple of Hercules, in the Sacred Area of the Republican Temples. It was built in the first quarter of the fifth century AD (opus latericium and vittatum). It consists of three rooms, an open court, and an enclosure on the east side. There are remains of marble decoration. The function of the building is unknown. To the north of the building are the remains of huge piers.