The double line of defensive walls visible in the Pasqualis Fund belongs to an advanced phase of the imperial age. At the beginning of the fourth century, if not a little earlier, the city was equipped with a new enclosure that at this point followed the course of the Natissa river, overlapping the shore line.

Three meters thick, it is built with abundant reuse material, coming from the demolition of buildings in other parts of the city. It was connected, on the internal side, by a rectangular tower, not protruding, which was covered after the excavations.

The outermost line, of lesser width, probably constituted an enhancement of the rear section, as a barrier, and was probably added in the middle of the 5th century. The defensive system was functional to the landing of boats, thanks to the preparations of the banks and the structured passages between the two lines of walls, so that the market squares behind them could be easily supplied with all goods.