Within the confines of the project of recovery of the building of the ex-episcopal seminary situated in the Piazza Regina Margherita di Palestrina,inside the covered courtyard and on the outside of the so-called Aula Absidata, archeological soundings were carried out. The excavation brought to light a series of walls in "opera poligonale," that defined a single terracing with ascensional stretch toward the summit of the hill, where it met the temple of Fortuna Primigenia. Basins were constructed on both of the walls in "opera poligonale." These were used for the gathering of the water that flowed from above and which then collected in a large cistern open to the sky, still used today for the gathering of the black waters. Between the rocky north and east walls and in support of the external walls of the Aula Absidata, was found a basin constructed in cocciopesto full of a series of strata of fill. The collapse of a roof including tiles and terracotta antefixes were discovered, probably belonging to the Aula Absidata itself. Ceramics and architectural decoration from the deposit dated it to the Julio-Claudian period. In the upper of the layers of the fill small constructive interventions were found, chronologically consistent with the transformation of the ancient building into an episcopal seat (16th century) and with the construction of the new building (18th century).