Ancient Harbours and Ports
The Edge Where Civilisation Meets the Sea
Ancient harbours were more than sheltered anchorages. They were the points where food, raw materials, luxury goods, soldiers, and ideas flowed between the urban world and the maritime one — and controlling them meant controlling the wealth and military power of an entire civilisation. The history of the ancient Mediterranean, the Red Sea, the Indian Ocean, and the South China Sea is to a remarkable degree a history of port construction, harbour administration, and the competition to dominate chokepoints.
Very little of this infrastructure is immediately visible today. The sea has risen, harbours have silted, wooden quays have rotted, and in many cases modern port construction has buried or destroyed the ancient evidence entirely. What survives — and survives remarkably — is often found beneath the water, preserved in the anaerobic muds of ancient harbour basins, or revealed by systematic archaeological excavation.
Caesarea Maritima: Building a Harbour Where None Existed
The harbour Herod the Great constructed at Caesarea Maritima on the coast of Judaea, built between roughly 22 and 10 BC, is one of the most astonishing engineering projects of the ancient world. The site had no natural shelter — a flat, sandy shore with no bay, inlet, or island. Herod's engineers, drawing on Roman hydraulic technology, built two enormous artificial breakwaters from hydraulic concrete poured into wooden forms on the seabed. Hydraulic concrete, made with pozzolana volcanic ash from Puteoli (modern Pozzuoli) in Italy, could set underwater and was strong enough to support the massive structures required.
The resulting harbour, named Sebastos (Greek for Augustus), enclosed an area of roughly 100,000 square metres — comparable to the harbour at Piraeus. It included a lighthouse, warehouses, a promenade, a temple to Rome and Augustus overlooking the basin, and ship sheds. The harbour silted severely after antiquity and the breakwaters partially collapsed, but underwater archaeological surveys since the 1980s have mapped the submerged remains in extraordinary detail, recovering concrete blocks, column drums, and the outline of the original basin.
Carthage and the Military Harbour
The ancient Phoenician city of Carthage, on the coast of what is now Tunisia, possessed what ancient sources describe as an unusual double harbour: a rectangular outer basin for merchant shipping and, connected to it by a narrow channel, a circular inner basin reserved for the war fleet. In the inner basin, a circular island held the admiral's headquarters and shipsheds arranged around the perimeter. This admiralty island — the cothon — gave the war harbour its characteristic form.
The harbour basins are still visible at Carthage, though much reduced in size. Excavations by the British Institute of Carthage during the 1970s and 1980s and subsequently by a joint international team confirmed that the circular harbour dates to the Punic period, probably the 3rd or 2nd century BC, and that the island did indeed support shipsheds of the standard trireme-era size. The site is now partly occupied by a yacht basin.
Piraeus and the Organisation of Naval Power
Athens controlled the eastern Mediterranean in the 5th century BC in large part because of Piraeus, the purpose-built port city connected to Athens by the Long Walls. The ancient harbours of Piraeus — the commercial harbour of Emporion and two military harbours, Zea and Mounichia — were equipped with stone shipsheds (neoria) arranged in rows around the inner basins. At Zea, systematic underwater survey and excavation since the 1990s has revealed the remains of at least 196 individual shipsheds, each designed to hold a trireme (a warship roughly 37 metres long and 6 metres wide) on a slipway above the waterline.
The Athenian navy at its height maintained hundreds of triremes, each requiring its own shed for dry storage when not in use. Managing and financing this fleet was the primary burden of the wealthiest Athenian citizens through the institution of the trierarchy. The shipsheds of Zea represent the physical infrastructure of Athenian imperial power; they are currently the subject of an ongoing excavation and visitor centre project at the foot of the Munichia hill.
Ostia and Portus: Feeding Rome
The city of Rome, with its million-plus inhabitants at the height of the empire, required a constant, enormous inflow of grain, oil, wine, and goods from across the Mediterranean. This supply chain terminated at the port complex at the mouth of the Tiber: the ancient city of Ostia and the later artificial harbour of Portus, begun by Claudius around 42 AD and greatly expanded by Trajan in the early 2nd century AD.
Portus was a hexagonal basin of roughly 33 hectares, connected to the Tiber by a canal. Around its perimeter and along the canal were warehouses (horrea) of enormous capacity. The Horrea Epagathiana at Ostia, one of the best-preserved warehouse complexes, gives a sense of the scale and organisation of this infrastructure. Trajan's harbour at Portus is visible today partly as a depression in the landscape near Fiumicino airport; aerial photography and systematic excavation have revealed its hexagonal outline and the surrounding warehouse complexes. A visitor centre and museum have been developed at the site.
Red Sea and Indian Ocean Ports
Roman maritime ambitions extended well beyond the Mediterranean. The port of Berenike on Egypt's Red Sea coast, founded in the 3rd century BC by Ptolemy II and used actively until around the 6th century AD, was the eastern terminal of a trans-desert road connecting to the Nile. From Berenike, merchant ships sailed to India, Arabia, and East Africa, returning with spices, textiles, ivory, and aromatics. The site has been excavated by an ongoing American-Polish team since the 1990s, which has recovered remarkable organic material: black pepper, Sri Lankan gemstones, Indian ceramics, and even a teak beam from a ship — all indicating the extraordinary reach of Red Sea commerce.
Myos Hormos (probably modern Quseir al-Qadim), another Roman Red Sea port, yielded ostraca — potsherd inscriptions — that give direct evidence of ship cargoes and merchant communications. The Periplus of the Erythraean Sea, a 1st-century AD Greek navigational manual, lists the ports of the Red Sea and Indian Ocean coast in detail, providing a documentary framework for interpreting the archaeological finds.
The Archaeology of Submersion
Many ancient harbours are now partially or wholly underwater, the result of eustatic sea-level rise, tectonic subsidence, and the compaction of ancient harbour fills. The harbour of Alexandria has been the most intensively studied: underwater archaeological investigations led by Franck Goddio since the 1990s have recovered fallen columns, statues, and the outline of ancient quays beneath the waters of the Eastern Harbour. The royal quarters of the Ptolemaic city, including structures identified as part of the Timonion built by Mark Antony, lie on the harbour floor.
Baia, the Roman resort city near Naples, has sunk by several metres due to volcanic ground movement, and its streets, mosaic floors, and building remains are now a snorkelling and diving site — one of the few places where visitors can swim above an ancient city.
Open the map to explore the locations of ancient harbours and port cities, from the submerged quays of Alexandria to the excavated shipsheds of Piraeus, and to find the maritime infrastructure that once underpinned ancient trade and power.