Two trenches (9x9x1.70m; 5x2.5x3.50) placed, one outside and one inside the late antique walls of Portus, near the entrance to the site brought to light a stretch of the eastern quay of the port of Claudius which at this point turned back towards the east thus forming a docking place. The un-faced cement structure appeared very eroded on its south side, whilst the west side was split in two by a deep crack. The stratigraphic sequence examined inside the walls revealed two warehouses built on the quay, between the end of the 4th century and the first half of the 5th century A.D., where until that time there had only been a small channel. The buildings were situated to the north and south of an axis which followed the Claudian urban plan. Between the middle and third quarter of the 5th century A.D. the warehouses were isolated from the quay by various interventions, whilst the passageway between them was blocked by a gate which prevented access to the city from the sea. Soon afterwards the walls were built. Their construction can be dated to the last quarter of the 5th century A.D. on the basis of the very rich material that was recovered from the dumps filling the adjacent docking space. These dumps abutted the facades of the warehouses, but the passageway was kept open by a postern gate which was subsequently walled up during the Gothic war. The area behind the walls was also covered by an enormous dump of earth which raised the ground level by over 3m. The subsequent phases were marked by the formation of a small necropolis (15 tombs were excavated) which extended over either side of the walls (mid 6th – mid/end 7th century ). The external defensive wall was restored using a construction technique which dates it to the 8th – 9th century. A lime slaking tank which overlies the burials was connected to this construction work. (Lidia Paroli)