This so-called Public Building is in the north-west part of the Sacred Area of the Republican Temples, to the north of the Temple of Hercules. It has been dated to the period of Trajan (opus mixtum, c. 112 AD). The function of most of the rooms is unknown. In one of the central rooms a cisterm with a waterwheel was installed that lifted ground water for use in the Baths of Buticosus to the east.
In the north-east room (directly to the west of the Tetrastyle Temple) wall-paintings have been preserved. The paintings on the east wall seem to have been divided by a pilaster resting on a marble base. On this wall, on a white background, are red aediculae and panels. There are connecting garlands of leaves and green bands. Four small, red-and-yellow depictions can be seen: two objects looking like vessels and two dolphins with a trident. On the south wall, above a red socle, is a high rectangular panel created by a yellow band and red lines. Inside is a dolphin with a trident. The paintings are probably Severan.
In the east part of the north wall is a wall niche with a base or altar in front. In front of the north wall is a low bench (h. 0.30 - 0.45).
