The construction of the imperial harbour of Rome started by the will of emperor Claudius in 42 CE. The river harbour of Ostia was becoming overloaded with commerical water bourne traffic, so in order to accommodate the intense maritime traffic was directed towards Rome coming from each part of the Mediterranean.

The Claudian harbour was inaugurated by emperor Nero in 64 CE, which consisted of a large basin between two long piers and was dominated by a large lighthouse. It is thought that, in monumentality, this lighthouse competed with the lighthouse of Alexandria in Egypt. The grand harbour complex consisted of internal navigational structures, piers and warehouses constructed around a small dock. This small dock was connected to the deeper Fossa Traiana via the transverse canal. These navigational features were already planned in the Claudian construction project to allow the river navigation towards the river Tiber.

In 110 CE, emperor Trajan decided to enlarge and make the harbour safer by constructing an internal hexagonal basin closely connected to the Claudian basin. The port was extended by the construction of large storage complex, the so-called Trajanic warehouses (magazzini Traianei). Around the same time a an imperial palace was also built for the representation and administrative functions. The multi functional complex of Severan warehouses (magazzini Severiani) was then built and at the beginning of the third century CE the storage spaces were further extended.

At the beginning of the fourth century CE emperor Constantine elevated the portus to the status of civitas and at the same time the first Christian community was formed around the Basilica Portuense. At the end of the fifth century CE the civitas was enclosed by walls, but over time it became subject to progressive cover-up and fading. Today the archaeological area of Claudian and Trajanic Harbours is situated some four kilometers from the actual coastline.

circa 90 CE

Inner Harbour (Darsena)
The inner harbour (Darsena) was the larger rectangular basin, measuring approximately 230 x 48 meters that formedpart of the original project for the Claudian port to act as an inland harbour. However, it was only completed under emperor Nero, as indicated by a brick stamp bearing the name Lucius Julius Rufus, who was the consul of Rome in 67 CE. Nevertheless, the darsena saw two mahor stages of development; one under Nero, the other under Trajan. The whares around this rectangular basin were lated protected by an outer brick wall during the reign of emperor Septimius Severus. Historical and archaeological study of the darsena basin is still in its early stages. The depth is estimated at about 8 meters (24 feet), but it has not been possible to establish whether or not the floor was paved, as was the case with the hexagonal lake and part of the Fossa Traiana. All the same, it is certain that the banks were, like port of the Trajan, with scarp walls to limit wave movement. To judge by its size and the type of bollards found, the basin was used for small coastal vessels and, most likely, as anchorae for the river boats and barges used to carry cargo up the river to Rome.

circa 90 CE

Transverse Link Channel
The channel or link-canal was built during the reign of emperor claudius and linked the port complex with the Fossa Traiana. In his description of the port complex in the sixteenth century CE, Antonio Labacco notes that there were two bridges over the canal. These can also be seen in some Renaissance period paintings of the area. Apparently, these were swing bridges as they had to allow mast-ships to pass through the canal. Today we can only a marked depression in the soil where the canal used to be; running north-south, together with stretches of the walls that used to border its entrance. Excavations in the 1930s CE discovered the remains of a few buildings, most likely the warehouses, that ran parallel to the canal on the west side. There were most certainly other buildings on the other side. Near theeast wharf a quadrangle room with tuff rock walls has been found, linked by an external path floored with common and glazed pottery dating back to the late eighth until ninth centuries CE. Signs of building in this area are thus documented from the Imperial Age to the early Middle Ages, proving that the canal was still being used until relatively later periods.

circa 90 CE

"Imperial Palace"
The so called imperial palace (Palazzo Imperiale) is the name give to a cast complex of buildings in the area between the two ports which first came to light in the mid-sixteenth century CE. Antonio Labacco described the complex briefly, mentioning large halls and rooms with sumptuous decorations, calling it the "Palace of the hundred columns", guessing that it was the "governor's palace". The special care taken over its construction and especially, the huge number of statues and other finds of unearthed between 1864 CE and 1867 CE led the archaeologists to assume that this was some kind of imperial residential complex. These buildings have yet to be systematically excavated and so it is difficult to date them accurately right now. The complex was obviously built in several stages and the building techniques used and the discovery of lead plumbing bearing the name of Claudius' wife, Messalina, indicate that the first stage probably took place while Claudius was still emperor. Brick stamps and certain structural details hint at the Trajanic period and them some work must have been carried out during the period of Marcus Aurelius. The full extent of this complex and the different purposes of each area, apart from two obvious thermal baths, are still unknown and so we can only guess. However, the previliged position and the quality of the decorations lead us to assume that this was an area used by the port authorities for their offices and high-ranking visitors, for embassies and accommodation for the imperial family.

The terraza di Traiano is part of this complex that looks over both ports at the same time. This building is some 200 meters long and includes a portico.

circa 90 CE

Dwelling from the Early Middle Ages
The dwelling dating back to the early Middle Age period was identified in the area behind the apse ofthe Basilica Portuense. This residential structure used the perimeter walls of a classic building (probably a warehouse) as its base, having patched them up with bricks and clay.

In a corner of the house there were three fireplaces, one on top of the other, built using recycled bricks and surrounded by layers of ash on the packed earth floor. Near the fires were examples of glazed pottery and terracotta from the eighth and ninth centuries CE. A thick layer of clay found throught the area points to the assumption that the house had mud wall. It is likely that this was a domus terrinea similar to those found in Rome in the Forum of Caesar, the presence of which in Portus is also recorded by early Middle Age sources.

A few infant tombs dating back to the seventh century CE have found in the layers of earth below the floor of this house, which lay about two meters above the original Roman floor. The remains had been placed in amphorae or on a tile. The custom of burying the dead within the city has been fully documented both in Rome and in other cities during late antiquity. Many tombs have been found in Portus (dating back to fifth and tenth centuries CE) in various areas, including the warehouses and around the Basilica Portuense.

Despite attempts to repopulate the area, mentioned by variou sources, the population of the city of Portus gradually dwindled during the early Middle Ages. After the year 1000 CE, archives mention that only a few places of worship and a handful of farms existed on what had basically become a rural area. The "salare" (salt warehouses) dotted around the area of Portus remind that the during the Middle Ages salt used to be extracted in the Campus Salinarum Romanarum (salt marshes) the the Romans had conquered from the Veii Etruscans in the days of early Roman Empire.

circa 90 CE

Early Christian Basilica
During the first half of the fifth century CE an existing structure was transformed in to an early Christian basilica (basilica paleocristiana). The church structure was in classic layout of a basilica thanks to the addition of semi-circular apse on the west side of the fourth century CE hall plus an annex. the naves and facade of the existing building were unchanged and the connections to other buildings in the surrounding area remained unchanged. The presence of the bishop's seat seems to call for the restructuring of the church, started in the second half of the fifth century CE and completed in the mid sixth century CE. The floor of the apse was raised and linked by steps to the presbytery area, now clearly distinct from the naces on account of the addition of a transept and the central corridor (schola cantorum). Various other important changes were also made to the structure of the building around the same time, such as the construction of a new annex on the right-hand side of the apse and, especially, the extension of the colonnade and the building of a new facade with a monumental three-part entrance leading to the main nave. THe basilica thus became some forty meters long and no further major changes were made to it over the following centuries. The only exception was the addition of a marble clad hexagonal baptism font in the eighth century CE to the left hand (western) nave probably the result of abandoning an external baptistery.

During the late eleventh century CE and early twelfth century CE, the dilapidated structures required external consolidation. Nearly all the arches in the colonnade on the left were reinforced with pillars that incorporated the old columns and supported new arches. Some of the old arches on the right were bricked up around the same time. The presbytery area was also altered, the schola cantorum was extended in the center o fthe nave and an ambon (pulpit) was built inside it. There are various signs that the building was isolated from the surrounding area until the mid thirteenth century CE, together with its use as a cemetery. The surrounding area had, in fact, become increasingly abandoned and buried during the ninth and tenth centuries CE. After building materials and marble was stripped, most of the church walls collapsed and over the course of the fourteenth century CE, perhaps during an earthquake. Some of the collapsed arches on the left can still be seen today in the eastern half of the main nave.

circa 90 CE

Claudian Portico
The monumental Claudian portico (Portico Claudio) was discovered in 1933 CE, during land reclaiming by Prince Giovanni Torlonia. The nature of the columns, several blocks of travertine stone deliberately roughly hewn and not finished, means it can be attributed to the times of the emperor Claudius. In fact, this type of surface treatment used in architecture finds close parallels in certain monuments in Rome dating back to the period of Claudius (porta maggiore and the arches in the Temple of Claudius on Monte Celio).

The imposing final structure created a monumental entrance to the west side of the port of Claudius and has a T-shaped plan, as it linked up with a wide colonnade street (some eight meters wide) running east-west. The complex was constructed during the reign of emperor Trajan (second century CE) and then Septimius Severus (third century CE) when it was incorporated in a large brick warehouse. One of the two arms of this portico (the so called colonnacce) was closed on both sides and became a sort of monumental atrium (hall) leading to the building complex used to store goods.

circa 90 CE

Severan Warehouses
The Severan warehouses (magazzini Severiani) was the huge brick building (some 190 x 130 x 25 meters) that dates back to the age of Marcus Aurelius, and not Septimius Severus as was previously thought, as proved by the brick stamps discovered in the foundations. This complex was built in at least two stages, after some previous small buildings on the site had been demolised. The warehouses have an L-shaped plan, the shorter side running parallel and adjacent to the wharf of the hexagonal harbour, while the longer side runs parallel to the entrance canal. The roof over the rooms was supported by huge cross vaults. In light of the calculated load capacity of the walls and pillars and the presence of various staircases we can assume that the building had more than one storey. The storage areas could be accessed directly from the hexagonal harbour and through an open gap in the canal leading in to the port. Moreover, the rooms were accessed by a wide corridor with alternating windows and doors facing the central area that was later bricked up. In late antiquite, the city walls were built against part of the west perimeter of the warehouses and strengthened on the inside with a wall built using opus vittatum (tuff and brick), though it would appear that this had no effect on the use made of the building. Around the middle of the fifth century CE, the complex (still presumably in use) suffered from the effects of subsidence and, perhaps, seismic activity.

circa 90 CE

Trajanic Warehouses During Late Antiquity
The warehouses continued to be used to store goods right up to the end of the Roman Empire. A law contained in the Theodosian Codex dating back to the year 364 CE called for the restoration of the warehouses in Rome and those in the port, proving that these were still playing an important role at the time. Part of the north facade was reinforced between the fourth and the fifth centuries CE by a continuous wall in opus listatum (alternate layers of tuff bricks and tiles). At the end of the fifth century CE the two sides of the warehouses facing the canal leading in to the port of Trajan were incorporated in the fortified wals around the city and strenghened at the rear by pillars that can still be seen today holding up the arches for the battlements. The actual date that these horrea (warehouses) were finally abandoned is not certain, but could be roughly the end of the sixth century or the early seventh century CE, given that tombs dating to this period have been found with in them.

One stretch of late antique wall running along the northern facade was restored during the early Middle Ages. The bricks and the other building materials laid in a staggered pattern and the sandy mortar would lead us to believe that the work was carried out at the same time as restoration of the antemurale.