The rooms situated in the southern part of the station dated to the beginning of the 12th century. They were built with medium to large yellow tufa blocks of pseudo polygonal and irregular rectangular form.

The urban block developed, in the form still recognisable in the 19th century cadastral register, on top of the early building complex between the middle and the end of the 12th century. The block did not directly overlie the earliest structures, but levels of sandy silt which came to form a marsh.

The evidence dating to this period was represented by a completely new construction which marked the beginning of the urbanisation of the area (beginning of the 7th century). It was situated outside the south-western stretch of the Greek fortifications and was constituted by a large rectangular building in squared yellow tufa blocks, divided into four rooms by the use of semi-pilasters. It had two staircases providing access to the upper floor, south of which was an entrance corridor, whilst to the west were another two rooms with trapezoidal plan. The simple typology of the rooms and their ample size suggests they were used as storage facilities related to the port area. The complex was enlarged and restored during the 8th century and destroyed between the end of the 9th and the 10th century. Prior to the 7th century the area was occupied only by temporary structures connected with glass and metal working.

Geo-archaeological core sampling demonstrated that this area corresponded with part of an inlet which reached the northern side of the piazza, below the stock-exchange building. From the 1st century A.D. onwards the area suffered progressive silting which led to the advance of the coastline which in the 6th century was seen to have reached the area of the southern edge of the piazza. It was only in the medieval period that the cordons of dunes formed that were to generate the two harbours, the Vulpulum at piazza Municipio and the Arcina in the area of the Molo piccolo.