Three years of excavations provided sufficient data for the reconstruction of a stratigraphic sequence ranging between the archaic (4th century B.C.) and the medieval (up to the 12th century) periods. The archaic period: The earliest structures were two stretches of wall built in squared grey tufa blocks and forming a corner. To the north-east of the _opus quadratum_ wall another structure was identified. This was constituted by a series of travertine slabs fixed vertically into the terrain, interpreted as a _sacellum_. The finds from the foundation trenches of these structures date them to the 4th century B.C. Republican period: In this period the structures were demolished and the area covered with a thick layer of stones from the river which constituted the foundations of the forum of _Nomentum_. Travertine slabs from the paving of the forum were found _in situ_, two were intact (circa 1.30 x 0.60 m). Furthermore, the excavation identified numerous imprints in the bedding left by the removal of the slabs. On the basis of the materials recovered the forum can be dated to the Republican period, between the 3rd-1st century B.C. Late antique period: the demolition of the forum and removal of the paving slabs was a gradual process. The beginning of this process is attested by a very large deep pit, dated to the 5th-7th century A.D. There was evidence of settlement in the forum in this period. Medieval period: following a period of abandonment (10th-11th century) during which several layers of colluvial deposit covered the forum. It was occupied again in the 12th century. The excavation revealed a substantial medieval phase constituted by a number of occupation levels and the remains of a structure in tufa blocks bonded with mortar. Also dating to the 12th century were several middens including one of considerable size.