I - 117 : Xerxes' incredibly large Fleet

The Olympias, a Replica of a Greek Trireme, was built in 1987 using original Design Plans

Few things amaze me more than the large numbers often mentioned in ancient texts. A telling example is Herodotus’ description of the Persian invasion fleet in 480 BC. According to his writing, the Persian ruler Xerxes sent 1’207 triremes to Greece. The trireme was THE naval work horse at the time. Invented by the Phoenicians, it weighted ca. 50 tons, was 35 – 40 meters long, about 6 meters wide, was manned by 165 rowers, 25 sailors and 12 marines. Building a trireme took a team of 40 skilled ship builders six months. To get his 1’200 trireme, the Persian Emperor had to mobilize his empire. Most triremes were built in the Levant, many on the coasts of Cilicia and the rest by Greek states in Asia Minor which were already under Persian rule.

Computer Rendering of a Trireme. Planks were made from Oak, Rest from Pines or Cedars

Apparently, heavy storms off Thessaly (400 ships lost) and off Euboea (200 ships lost) wreaked havoc on the Persian fleet. We are “invited” to believe that Poseidon, the Greek God of the Seas, destroyed half of the Persian fleet even before it arrived in Greece. What better way for Herodotus to “prove” that the Gods were on the Greeks’ side. At a 50% loss rate, any fleet loses unit cohesion and becomes combat ineffective.

In this Painting of Wilhelm v. Kaulback (1868), the Godess Artemis fights with the Greek

However, we know from other sources that about 700 Persian triremes made it to Salamis in good order. Something in Herodotus’ numbers smells fishy. The Persians arrived battle ready. But then they made the mistake of attacking the Greek fleet inside the Salamis Bay. In the confined space they could not use their 2:1 numerical superiority and eventually lost. More than 300 Persian ships were sent to the bottom of the sea.

The Position of the two Fleets at the Beginning of the Naval Battle of Salamis in 480 BC

Is there a way to cross-check Herodotus’ numbers? There are few other sources. Can we check indirectly? Was it possible to build a fleet of 1’200 trireme for the invasion of Greece? What logistic was necessary to support it? For 3 long years Xerxes meticulously prepared his campaign.

In the 5th Century BC, the seaside Mountains of the Levant and Cilicia were still full of Pine and Cedar Trees - this photo is from the Lebanon where only few Cedar Forests survived

This gave him enough time to cut 30’000 cedar or pine trees (25 per trireme), procure flax for the sails, hemp for the  ropes and cast all the 500 kg heavy bronze rams. Assuming that it took 1 year to obtain and prepare the materials and that 40 men indeed could build 2 ships per year, it requires 300 teams or 12’000 men to get the desired number of triremes. The number of workers and material is definitely within the capacity of the Persian Empire which counted 50 million people at the time.

Bronze Ram for a Trireme to sink Enemy Ships

What about sustaining the fleer once it was at sea? Am basing my calculation on a campaign season lasting 4 months (125 days), and each rower consuming 6’000 cal per day. A kilo of bread has about 2’500 cal. One kilo of meat (80% protein, 20% fat) about 5’000 cal. A rower had to consume daily 0.65 kg of meat and 1 kg of bread to meet his energy requirements.

Manning a Trireme was physically demanding. Rowers were Volunteers and fought as Foot Soldiers once the Triremes got entangled - the Trireme fought without Sails

I now multiply these numbers with 1’200 trireme x 200 men per ship x 125 campaign days. The fleet would need 30’000 tons of bread and 20’000 tons of meat – quite a number! To transport so much food, Persia would need at least 1’700 support vessels of the 30-ton type we saw in Kyrene / Bodrum last summer. Herodotus mentioned somewhere in his text that there were 3’000 cargo vessels. If the larger, 300-ton standard Roman cargo ship was used instead, the number of Xerxes’ supply vessels would drop to 170 ships. The truth is probably somewhere in between. Maybe Xerxes could support his fleet with 800 supply ships? Still a large number but again well within the capacity of the Persian Empire.

Xerxes' Supply Train must have looked similar to these coastal Gulets in the 19th Century

This takes us to the question of port size. In antiquity, galleys followed the coastline and hopped from port to port to avoid being caught in bad weather. Could not find out where Xerxes exactly anchored on his way from the Dodecanese to the Dardanelles to Athens. Ports in the Aegean though were all of similar size. Large mega ports came only with the Roman Empire. As a proxy, am going to use the ports which Darius’ brother Artaphernes and his son, Admiral Datis, used in 490 BC. Their fleet of 200 triremes took the route via Lindos (Rhodes), Samos (probably Pythagoreios), Naxos and Delos. 

The Lindos Harbor could probably accommodate 400 ships of Trireme Size

Was the port of Lindos big enough for 200 triremes?  The surface of a trireme is about 220 square meters (37m length x 6 m width), covered by oak planks. The natural bay north of the Lindos Acropolis measures about 900’000 square meters. It thus can accommodate 400 densely packed triremes. So yes for the fleet of Admiral Datis but no for the fleet of Emperor Xerxes. And definitely no for the valuable cargo vessels. Lindos was too small.

About 250 Triremes would fit into the Commercial Port of Knidos which we visited last Year

In Delos, just next to Mykonos, it was not any better. Mykonos is too windy and rough for a fleet to stay. The trireme would have to take shelter in Delos. The port is 200 meters wide and 500 meters long. With 1'000’000 square meters, it is a bit bigger than Lindos. But still not enough place for an entire fleet of 1'200 ship. I did the same calculation for Knidos and Samos and got similar results. Xerxes’ fleet as mentioned by Herodotus was too big.

Even the relatively wide and open Harbor of Delos would be too small for Xerxes' Fleet

Somehow, I get the feeling that Herodotus’ numbers are exaggerated. It was a common practice in antiquity to inflate an enemy’s numbers. It makes your own victory more heroic and glorious. Based on sober calculations though, a Persian fleet with 700 triremes and 400 supply ships makes sense. It could be divided into 2 echelons to deal with the scale issue. This smaller number though makes Poseidon’s “divine” intervention off Thessaly and Euboea impossible. But that story is questionable anyway. The ports of Asia Minor and Greece could handle a Persian fleet half the size of Herodotus’ number

Herodotus (485 - 425 BC) is called the Father of History - Statue is in Vienna at Parliament

The only other source that corroborates my thinking is the Greek Writer Aeschylus. He fought at Salamis and mentioned they were 310 triremes to fight a foe twice as numerous. In the narrow straits, he and his countrymen outmanoeuvred the Persians and sank half of their fleet. Had Xerxes had 1’200 triremes, as Herodotus claims, he would have resumed fighting the next morning. The loss of 300 trireme would have left him with 900 fighting ships - enough to fight another day. Persian Emperors did not mind losses - even when severe.

Artist Impression of Xerxes watching the Performance of his Fleet with Horror

What is truly rermarkable is the fact that Persia could build, man and maintain a fleet of 700 triremes and 400 support vessels. It speaks for their superb organizational capacity. To assemble such a huge fleet plus maintain it at sea was an immense logistics challenge. For me, it is thus no accident that the Empire – despite losing the war in Greece – lasted for another 150 years before finally succumbing to Alexander the Great.

Xerxes' Route to Athens crossed our Way this Summer from Rhodes to Crete

This summer, on our way from Rhodes to Crete, we will cross the route that Xerxes took on its way to Athens 2’500 years ago. It must have been a tremendous sight to watch more than one thousand sails steadily moving – at a speed of 5-6 knots - towards Greece. The Persian logisticians who made all this possible have my full respect. As we say in the army:  “Amateurs talk about tactics. Professionals about logistics.”  The Persians were true professionals.

Our Sailboat for this Summer, the "Myra" is with 27 meters a bit shorter than a Trireme