The ancient port of Rome was Ostia, which was located at the mouth of the Tiber River. It was founded in the 4th century BC and served as the main port of Rome for centuries. Ostia was a major trading center and was home to many merchants and traders. It was also an important military base and was used to defend the city from attack. In the late Roman Empire, Ostia declined in importance and eventually fell into disrepair. Today, it is a popular tourist destination and a reminder of Rome's past.