In the period of Domitian (81-96 AD) a brick temple was erected in the centre of the Square of the Corporations, facing the theatre. Traditionally the temple has been assigned to Ceres, a deity related to grain. This identification is perhaps supported by the phrase ad Annonam, "near Annona", on the Altar of the Origins of Rome that was found in the Shrine of the Altar of the Twins at the south end of the west porticus of the Square of the Corporations. Annona herself, personification of the food supply, also seems a good candidate. Serapis and Vulcanus have also been suggested. According to Van der Meer the temple may have been built by Domitian himself and was dedicated to the cult of deified Emperors. An arm of a colossal statue (of Domitian?) was found in the south-west part of the square.

The vestibule was reached along a staircase with perhaps eleven marble steps (the present steps are a restoration). On one of the steps is a graffito of an elephant. The staircase is flanked by two large water basins. In front of the vestibule were two marble columns. The walls of the cella have disappeared almost entirely. The pavement was made of marble slabs. Along the walls were stone benches. The central part of the northern bench is protruding.