Available evidence indicates that the port continued to witness intense commercial activity until the later 5th century AD. At this point, the port authorities established a wall circuit that enclosed all of the buildings that clustered around the Trajanic basin and the maritime façade on the western side of the Darsena. The intention was clearly to ensure that this innermost area of the port, which remained the scene of commercial activity crucial to Rome, was protected from external threats.
Simultaneously, however, evidence from imported ceramics suggests that the intensity of commercial pursuits began to wane. Moreover, the overall extent of the port also started to contract, and Christian churches were established. By the 6th century AD, the Claudian basin had largely silted up and even though the port was the focus of a struggle between Byzantines and Ostrogoths during the Gothic wars (AD 535-553), buildings were abandoned or demolished and burials appeared within their ruins.