Xerxes Canal

The Athos peninsula in northeastern Greece, that juts into the Aegean Sea for some 50 kilometers, was once bisected by a canal a hundred feet wide. The canal was built by king Xerxes I of Persia in the 5th century BC as part of the preparations for his intended invasion of Greece in 480 BC. The motivation behind this monumental earth-moving project stemmed from the disastrous experience of Persian commander Mardonios, who, twelve years earlier, attempted to navigate his fleet around the perilous cliffs of the Athos peninsula during the First Persian invasion of Greece. The peninsula's treacherous waters claimed a considerable portion of King Darius's fleet—some 300 ships and 20,000 men—during a storm.

The Xerxes canal as it would have appeared if it still existed. Image credit: Konstantinos Tamateas/Wikimedia Commons

In a bid to avoid a similar catastrophe, Xerxes tasked his engineer Artachaees with constructing a canal across the narrowest stretch of the peninsula. Over three years, forced laborers toiled to create a canal spanning two kilometers (1.2 miles) in length and 100 feet in width, allowing passage for two triremes simultaneously. The canal's design featured inward-sloping sides, narrowing to roughly 50 feet at the bottom and lying approximately 45 feet beneath the surface.

Upon the successful passage of the Persian fleet through the canal en route to the Battle of Artemisium, Xerxes made little effort to preserve the canal as a permanent waterway. Over time, the canal fell into disuse and became filled with silt. Remnants of this engineering marvel can still be observed on the isthmus between Nea Roda to the north and Tripiti to the south, marking the narrowest point of the Athos peninsula. This canal not only stands as a remarkable testament to Persia's brief dominion over northern Greece but also represents one of the earliest examples of marine engineering in history.

The primary source documenting the construction and existence of the canal is the ancient Greek historian Herodotus, who wrote:

I will now describe how the canal was cut. A line was drawn across the isthmus from Sane and the ground divided into sections for the men of the various nationalities to work on. When the trench reached a certain depth, the laborers at the bottom carried on with the digging and passed the soil up to others above them, who stood on ladders and passed in on to another lot, still higher up, until it reached the men at the top, who carried it away and dumped it. Most of the men engaged in the work made the cutting the same width at the top as it was intended to be at the bottom, with the inevitable result that the sides kept falling in, and so doubled their labor. Indeed they all made this mistake except the Phoenicians, who in this - as in all practical matters - gave a signal example of their skill. They, in the section allotted to them, took out a trench double the width prescribed for the actual finished canal, and by digging at a slope gradually contracted it as they got further down, until at the bottom their section was the same width as the rest. In a meadow near by the workmen had their meeting place and market, and grain ready ground was brought over in great quantity from Asia.

Herodotus believed that Xerxes constructed the canal not only to facilitate an attack upon Greece but also to show his might:

...it was mere ostentation that made Xerxes have the canal dug - he wanted to show his power and to leave something to be remembered by. There would have been no difficulty at all in getting the ships hauled across the isthmus on land; yet he ordered the construction of a channel for the sea broad enough for two ships to be rowed abreast.

The canal was mentioned again in passing by Thucidydes in The History of the Peloponnesian War written about eighty years after the war:

After the taking of Amphipolis, Brasidas and his allies marched to the so-called Actè, or coastland, which runs out from the canal made by the Persian King and extends into the peninsula; it ends in Athos, a high mountain projecting into the Aegean sea.

Demetrius of Scepsis also stated based on first-hand information that there had, indeed, been a canal there, but he could not trace all of it.

While historical records affirm King Xerxes's commissioning of a canal, historians have debated whether the famed Canal of Xerxes was really dug all the way from coast to coast. Some skeptics have cast doubt on its existence altogether, citing geological challenges such as a rocky plateau that they argue would have rendered construction implausible with the technology available at the time.

At least three separate modern land surveys, conducted by the Frenchman M. Choiseul-Gouffier in the 18th century, by T. Spratt of England in 1838, and by the German A. Struck in 1901, all found evidence of the canal in the central part of the isthmus. But as late as 1990 the length and width of the canal was in dispute, as was the question of whether the canal reached all the way across the isthmus or if ships were dragged through parts of it.

Map of Athos peninsula showing the location of Xerxes canal. This map appeared on the report by T. Spratt.

It wasn't until thirty years ago that a collaborative effort between British and Greek researchers conducted a groundbreaking geophysical investigation, unearthing conclusive evidence of the canal's existence. Utilizing geological data collected from beneath the earth's surface, where the structure now lies buried, these scientists meticulously mapped out the canal's dimensions and course. Their findings corroborate the descriptions provided by Herodotus, which some scholars have long regarded with skepticism.

“From the analysis of sediments in the canal, we know that it probably had a short lifetime,” said Dr. Richard Jones, the lead researcher on the project and an archaeologist at the University of Glasgow. “The Persians did not think of it as a monument that would remain for centuries. Once their ships were through, that was the end.”

“It was a colossal enterprise," added Dr. Ben Isserlin, an archaeologist at the University of Leeds who started the canal exploration project in the early 1990s. “There were no pulleys. So the workers had to shovel earth into baskets and pass them along, from one person to the next, all the way to the top.”

After completion of the canal, the the Persian fleet made it safely to the Aegean Sea, where it was joined by the troops that had traversed the land route from the north, thus forming a formidable force poised to advance into Greek territory. Xerxes's soldiers then launched an assault on the Greek coast, penetrating deep into their territory and inflicting significant damage, including the destruction of Athens. Despite their initial successes, the Persians ultimately faced defeat at the hands of the Athenians in a decisive battle, marking the end of their fleeting imperial presence in Europe.

As the tides of history shifted and empires rose and fell, the canal that played a crucial role in facilitating Xerxes's ambitious campaign gradually faded into obscurity. Over time, it got buried in silt and forgotten.

References:
# The Canal of Xerxes: Summary of Investigations 1991-2001, The Annual of the British School at Athens
# Xerxes' Canal across the Athos, Livius.org
# Persian Canal Discovery Is Testament to Ancient Engineering Skills, The New York Times