Byzantine Culture

History · Guide

The Byzantine Navy

The Byzantine navy held the eastern Mediterranean for eight centuries. Its ships, crews, tactics, incendiary weapons, and the slow loss of the sea to Venice and Genoa.

Rome had not needed a serious navy for three hundred years. Once Actium settled the civil wars and Pompey’s campaign had cleared the pirates, the Mediterranean was a Roman lake with no rival fleet on it, and the imperial squadrons at Misenum and Ravenna decayed into coastguards. The seventh century ended that arrangement permanently. From the 640s the Arab conquest of Syria and Egypt put shipyards, timber, sailors and a hostile power on the far side of the same sea, and the eastern empire had to become a naval power again within a generation.

It managed it, and for roughly four hundred years the Byzantine navy was the most technically advanced fleet in the world. Then, between about 1080 and 1204, it was dismantled by a series of decisions that each looked reasonable at the time, and the empire ended by having to hire the ships of the Italian republics that were eating its trade.

The Ships

The Dromon

The standard Byzantine warship from the sixth century to the twelfth was the dromon (“runner”), a development of the late Roman liburna. It differed from the classical galley in three important ways: it was fully decked, its oars were worked through ports rather than over the gunwale, and it carried a lateen rig on one or two masts rather than a square sail.

The classic form described in the tenth-century sources had two banks of oars, about twenty-five oars a side per bank, and a crew of roughly two hundred and thirty — a hundred and twenty oarsmen on the lower bank, a hundred and ten on the upper who were also the fighting men, plus officers. A lighter single-banked type, the galea, served as a scout, and the heavy chelandion carried horses.

The ram had gone. Classical galley warfare turned on holing the enemy at the waterline; the dromon carried instead an above-water spur designed to ride up over the opposing hull and break its oars, which disabled a ship without sinking it — and a captured ship was worth more than a sunk one.

Armament

Each dromon carried a siphon in the bow for Greek fire: a pressurised, heated petroleum mixture pumped through a bronze tube and ignited at the muzzle. It had a short range, it was dangerous to the crew, it could not be used in a strong headwind, and it was decisive in confined water. The Arab and Rus fleets that met it at Constantinople in 678, 718 and 941 broke off in each case.

Ships also carried crossbow-like toxobalistrai, hand-thrown clay pots of incendiary or noxious mixtures, caltrops to scatter on an enemy deck, and marines in mail. Leo VI’s Taktika devotes a whole constitution to naval warfare and is the best surviving guide to what a tenth-century sea fight was meant to look like: form line abreast, keep the reserve to windward, aim for the enemy’s flank, use the fire only at close range, and never let the line be broken by a pursuit.

Organisation

From the late seventh century the fleet was organised on the same provincial lines as the army. The Karabisianoi, the first standing naval command, was replaced around 700 by the naval theme of the Kibyrrhaiotai on the south Anatolian coast, joined later by the themes of the Aegean Sea and Samos. These provided ships, oarsmen and marines from maritime districts on the same land-for-service basis as the soldier-farmers of Anatolia.

At the centre was the imperial fleet at Constantinople under the droungarios tou ploimou, one of the senior officers of the state. Provincial fleets defended their coasts; the imperial fleet was the striking force.

Oarsmen were free men, paid, and usually also the fighting crew. Galley slavery in the Mediterranean is a later, largely Ottoman and western European institution; Byzantine sources do not describe it.

What the Navy Did

It saved the capital three times. The Arab sieges of 674–678 and 717–718 were broken at sea, and the Rus attack of 941 was destroyed off the Bosphorus by a scratch force of old ships fitted with siphons.

It fought a long, losing war for the central Mediterranean. Crete fell to Andalusian exiles in the 820s and became a raiding base for a hundred and forty years; Sicily was lost piece by piece between 827 and 902; Thessalonica, the empire’s second city, was sacked from the sea in 904. The recovery of Crete by Nikephoros Phokas in 961 — a meticulously planned amphibious operation with a landing under covering fire from ships — was the outstanding Byzantine naval achievement and the beginning of a fifty-year reconquest.

It kept the sea lanes of the empire open. The grain of Egypt was gone after 642, but the corn of Thrace and Anatolia, the silk and luxury trade, and the movement of armies all depended on shipping. The administrative and commercial framework is described in the Byzantine economy.

The Loss of the Sea

The decline is easy to date and uncomfortable to explain.

In 1082 Alexios I Komnenos, desperate for ships against the Normans in the Adriatic, granted Venice exemption from commercial duties throughout the empire in exchange for naval help. It was a rational emergency measure. Its effect over the following century was to place Byzantine seaborne trade in Venetian hands, remove a large slice of customs revenue, and remove the incentive to maintain a fleet the empire could no longer afford.

Successive emperors tried to reverse it. Manuel I built ships and played Genoa against Venice; his arrest of all Venetians in the empire in 1171 produced a war he could not win. By 1203 the empire could put a handful of rotting hulls into the water, and the fleet of the Fourth Crusade — Venetian ships, Venetian crews — entered the Golden Horn after breaking the chain across its mouth.

The historian Niketas Choniates blamed a single official, the megas doux Michael Stryphnos, for selling off the fleet’s anchors, sails and rigging for personal profit. The accusation is memorable and probably unfair as a total explanation, but it points at something real: a maritime establishment that had stopped being a priority long before it was needed.

After 1261

The Palaiologoi made one serious attempt at naval revival. Michael VIII rebuilt a fleet in the 1260s, including a corps of Gasmouloi — men of mixed Greek and Latin parentage from the former Latin territories, who made excellent marines. Andronikos II disbanded it in 1284 as an economy, reasoning that Genoese ships could be hired more cheaply. Pachymeres, who watched it happen, records that the unemployed crews went over to the Turkish emirates of the Aegean coast, where their skills contributed to the rise of Turkish sea power.

By the fifteenth century the empire’s naval defence was a chain across the Golden Horn and whatever Italian galleys happened to be in port. In 1453 four ships — three Genoese and one imperial — fought their way through the Ottoman blockade in one of the last actions of Byzantine naval history, and were watched from the shore by the sultan, who is said to have ridden his horse into the water in fury.

How Greek Fire Was Delivered

The mechanics deserve more attention than they usually get, because they explain the weapon’s tactical limits.

The apparatus had three parts: a sealed bronze container holding the mixture, a pump — almost certainly a force pump of the type Hero of Alexandria describes — and a bronze nozzle, often cast as a lion’s or beast’s head, projecting over the bow. A brazier heated and pressurised the container; the pump drove the liquid out; an ignition source at the muzzle lit it.

Every part of that was dangerous on a wooden ship in a seaway. The container could rupture; the pressure had to be judged; a shift of wind blew the flame back over the crew.

The range was short — tens of metres, not hundreds — which meant the weapon was useless in open water against a fleet that could stay away, and decisive in the confined water of the Bosphorus, the Golden Horn and the Hellespont, where an enemy had to come close. That geography is why the fire saved Constantinople three times and never won a battle in the open Mediterranean.

Portable hand-siphons are also described, and grenades of clay or glass filled with the mixture were thrown from the fighting tops.

Manning the Fleet

A tenth-century imperial fleet of a hundred dromons required something over twenty thousand men, which is comparable to a large field army and considerably more expensive per head.

Crews came from the naval themes on a land-for-service basis, from the maritime populations of the Aegean islands and the south Anatolian coast, and increasingly from paid recruitment. The Book of Ceremonies records the establishment and pay of the fleet sent against Crete in 949 in enough detail to reconstruct the cost, and it is enormous — one of the reasons expeditions on that scale were attempted perhaps once a generation.

Oarsmen were free, paid and armed. This is worth repeating because the image of the chained galley slave is so firmly attached to Mediterranean rowing: it belongs to the sixteenth century and later, and Byzantine sources describe nothing of the kind.

The Sources

The naval history rests on a narrow base: the tenth-century constitution on naval warfare in Leo VI’s Taktika, the inventories in the Book of Ceremonies, scattered narrative accounts of particular engagements, a handful of Arabic descriptions from the other side, and the ship graffiti and wreck archaeology of the last thirty years.

The Yenikapı excavations in Istanbul, which uncovered the silted harbour of Theodosius during construction of a rail tunnel from 2004, produced thirty-seven Byzantine wrecks of the fifth to eleventh centuries — round merchant ships and several light galleys. They are the first Byzantine hulls ever excavated, and they have already corrected assumptions about construction technique, confirming the shift from shell-first to frame-first building over this period. Much of what will be known about Byzantine ships in twenty years will come from that site.

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