Massive fortifications and sunken ship-sheds thousands of years old have been found in Piraeus, the harbor city of Athens. The discoveries are part of the partially sunken port that played a pivotal role in the famous Battle of Salamis, against the Persian Empire, the naval conflict that saved Greece and the young democracy of Athens in 480 BCE.

After the Battle of Marathon ten years earlier, in 490 BCE, the Athenian statesman Themistocles outlined a military defensive program against the Persian invaders that was based entirely on sea power. As Plato put it, "Themistocles robbed his fellow-citizens of spear and shield, and degraded the people of Athens to the rowing-pad and the oar."

Construction work in Piraeus had already begun in 493 BCE (also on Themistocles advice). Now, recent underwater excavations conducted by ZHP Project, which combines land and underwater archaeology of the ancient Zea and Mounichia harbors in Piraeus, have uncovered naval bases and huge fortifications that testify to the might of the Athenian Navy that once ruled the waves.

“We have identified, for the first time, the 5th century BC naval bases of Piraeus – the ship-sheds, the slipways and the harbor fortifications," Bjørn Lovén, director of the Zea Harbor Project, told Haaretz (for more on the Zea discoveries, click here).

Open gallery view The harbors of the Piraeus are heavily polluted. Archaeologists wore chemical-resistant dry-suits and full-face masks with positive-pressure valves to seal themselves. Credit: Vassilis Tsiairis

The discoveries place the naval bases of Piraeus at the historical and archaeological level of importance as the Acropolis and Parthenon, or the Athenian Agora, Lovén adds.

Yet the monumental finds were the result of serendipity.

Catch of the day

In 2010, an old fisherman guided the archaeologists to the naval bases dating to the time of the battle of Salamis. He knew of them: As a child, he used to sit and fish on an ancient column rising from the sea on the northern side of Mounichia in the Piraeus, on what was once part of the old harbor.

Open gallery view An archaeologist excavates the early shipsheds at Mounichia Harbor in the Piraeus. Credit: Vassilis Tsiairis

After the fisherman had guided the divers through a murky labyrinth of mooring chains, anchors and modern debris, where underwater visibility could be as little as 20 centimeters, the excavators stumbled upon their greatest find: The remains of an ancient monumental wall resting on the seabed, with large foundation blocks in three colonnades.

Soon six ship-sheds were discovered and excavated – ancient shelters constructed as roofed ramps that once housed the ancient warship, the triremes (named after its three levels of oar-banks). Triremes were at least one of the classes of ships that had partaken in the battle of Salamis in 480 BCE, in which the outnumbered Athenian alliance, led by Themistocles, defeated the Persians under Xerxes in a brilliant naval maneuver.

With an additional nine found in Zea Harbor, the underwater excavations have unearthed the remains of 15 ships-sheds from 5th century BCE.

Based on pottery and carbon-14 dating from a worked piece of wood found inside the foundations of a colonnade, the team dated the ship-sheds to around 520-480 BCE, or shortly thereafter.

Open gallery view Artistic reconstruction of a trireme housed in the earliest shipsheds at Mounichia Harbor. Credit: Yiannis Nakas

“These ship-sheds were built in the years of the young Athenian democracy. It is an enticing thought that some of the Athenian triremes that fought against the Persians at Salamis in 480 BC were most probably housed in these ship-sheds,” says Lovén.

“Keep in mind that all social classes rowed and fought aboard triremes in the Battle of Salamis. I strongly believe that this very important battle in the Salamis Strait, just west of Piraeus – a turning point in world history – created an immensely strong bond among most of the citizens. That is how the Athenian navy was to develop into the backbone of the world’s first democracy during the 5th century BC. What we’ve been excavating, in essence, are the material remains of that extraordinary historical development,” Lovén added.

Athens' naval might

The naval victory in the Battle of Salamis liberated the Greeks from the Persian yoke. With the Persian ships gone from the Aegean, the nature of the allied Greek states headed by Athens, called the Delian League, gradually changed from defensive to expansive. Athens was freed to deploy large fleets throughout the Mediterranean, which it used to carve out the great Greek empire. (Not a few states in the area were forced to join the league against their will.)

Open gallery view Satellite photo of the modern Piraeus showing the configurations of the three harbours, Kantharos, Zea, and Mounichia. Credit: GoogleEarthPro

To preserve its empire and secure its wealth, which stemmed from maritime trade and levying tax from subject states, Athens also maintained a large war fleet. At its peak, Piraeus hosted about 400 triremes requiring crews of 80,000 sailors and soldiers.

At the height of Athens' power, 150 island and coastal cities were within her domain. Athenian triremes patrolled the Black Sea in the North, the Israelite coast in the east, and the Nile delta of Egypt in the south.

Now the Zea Harbour Project excavation has uncovered part of this juggernaut of a war machine.

An impregnable harbor

Piraeus was never taken by an enemy from the sea-side, because of its excellent system of coastal and harbor fortifications.

Open gallery view A column base in the early shipsheds at Mounichia Harbor in the Piraeus. Credit: Vassilis Tsiairis

New evidence found after the Zea Harbor Project include extensive underwater walls and along the Zea coastline, and a previously unknown phase of building.

"It became clear that the harbor was a so-called Limen Kleistos, a ‘closed harbor’, like most naval harbors of the time," says Mads Møller Nielsen, one of the researchers involved in the project, who studied the harbors fortifications. "This means that the harbor was fortified on the sea-side with massive fortified moles, and had a large central entry gate through which all ships had to pass to get inside.”

Ancient Greek sources tell how the harbor could be sealed with the help of a chain hauled between two large square towers on each side of the harbor entrance. Not only would enemy ships have had to vanquish both towers at the entrance: they'd have to do so under constant barrage from fortifications along the coast. "It would have been an almost impregnable harbor,” Møller Nielsen says.

Open gallery view Piraeus port today: Thousands of years later it's still in use. Credit: Bloomberg

The port at Piraeus may have been impregnable, but Athens was not. By 431 BCE its dominance in the Eastern Mediterranean brought it into conflict with Greeces major land power, Sparta, and its allies. It was a long and bitter war but finally, Athens lay defeated in 404/3 BCE and the Spartans tore down the Piraeus naval bases and fortifications, leaving the home of the mighty Athenian fleet in ruins.

The Zea Harbour Project operates under the auspices of the Danish Institute at Athens and is directed by Dr. Bjørn Lovén. The project is supervised mainly by the Ephorate of Underwater Antiquities, and have conducted some investigations on land under the Ephorate of Antiquities of West Attica, Piraeus and Islands. The Carlsberg Foundation has been the project’s principal sponsor since 2004.