
Ostia, founded in the 4th century BCE, was the original port of Rome and functioned as such through the 1st century CE. By that time, it was clear that new harbor facilities were needed to meet Rome's expanding trade, particularly the massive amount of imports flowing into the capitol. Claudius began construction on a new port a few miles north of Ostia, which was simply named Portus (Latin for port or harbor). This new harbor featured a large mole and lighthouse and greatly increased the amount of ships that could bring goods into Rome. Portus changed little until the reign of Trajan, who felt the need for greater expansion. Trajan had a giant hexagonal port built that was connected to Claudius' port and the Tiber via a large canal. This hexagonal port was lined with docks and warehouses for the unloading and storage of good. By this time, Portus supplanted Ostia as the major port of Rome. Portus remained important through the rest of Roman history, though eventually fell out of use by the 6th century CE.
Today, the name Portus is misleading since the modern coast is about two miles away, due to centuries of silting by the Tiber. Just to the north of Portus is Leonardo da Vinci-Fiumicino Airport, which covers part of the ancient city. The most noticeable feature of ancient Portus is Lago di Traiano, which was built as Trajan's hexagonal port.