Miniature depicting the Byzantine Navy repelling the Russians during the siege of Constantinople in 941

The Byzantine Navy: From maritime dominance to decline

The Byzantine navy was vital to the empire’s defense and dominance, securing trade routes and repelling invasions with innovations like Greek Fire. Though initially a maritime superpower, it gradually declined due to economic challenges and reliance on foreign fleets.

The Navy in the early Byzantine time: the golden time.

In the 6th century, Byzantine warships established control over the seas by recapturing Carthage and destroying the Vandal fleet. During this period, the navy primarily functioned as a police force operating from Constantinople and various Mediterranean bases. However, in the mid-7th century, the emergence of Slavic pirates and the development of Arab naval power under Mu’awiya necessitated a major naval reorganization. The fleet of the Karabisianoi was created to defend the Byzantine coastline and the approaches to Constantinople.

Following the dissolution of the Karabisianoi under Leo III, regional fleets were established, financed independently through the naval strateia. These fleets were organized within the exclusively maritime themes of the Kibyrrhaiotai (by 732), Aegean Sea (by 843), and Samos (by 899). The imperial fleet (basilikon ploimon), based in Constantinople and commanded by the droungarios tou ploimou, was responsible for protecting the capital and undertaking expeditions, often with contributions of ships and manpower from the thematic fleets. The navy achieved its greatest successes in the 10th century, notably with the destruction of the Rus’ fleet in 941, the reconquest of Crete in 961, and Cyprus in 965.

Miniature of the Skylitzes manuscript showing the use of the Greek Fire by the Byzantine navy

The Greek Fire, an incendiary weapon said to have been invented by Kallinikos to defend Constantinople from the Arabs in 678, was a redoutable weapon to strenghten the naval power. The mixture, probably of crude oil with resine and sulfur, was heated and projected via a pump (siphon) through a bronze tube (strepton). The liquid jet was ignited either as it exited the tube or by flaming projectiles fired after it. Frequently used during naval battles, but also in the land military, it ensured a tactical advantage and proved redoutably efficient, for instance in the siege of Constantinople by the Arabs in 678 or by the Rus´ in 941. The secret of the composition and operation was a closely guarded secret which got lost after the Fourth Crusade.

Decline of the Navy in the Middle Byzantine times.

The navy began to decline during the 11th century. The thematic fleets disappeared, and by the 12th century, naval command, financing, and recruitment were centralized in Constantinople. Taxes initially raised for the navy were diverted into the imperial treasury under John II Komnenos. From then on, fleets were constructed on an ad hoc basis, and alliances were formed with naval powers such as Venice to secure ships and manpower for expeditions. While the Komnenian navies experienced occasional successes, the Venetians and Genoese gradually dominated the Aegean, and even the Byzantines came to acknowledge the superior seamanship of the Italians.

Reduced naval ambitions in the Late Byzantine times.

Byzantine navy, light galley depicted on an icon in the Byzantine Museum in Athens
A light galley depicted on a 14th century icon

The decline of the Byzantine navy under the Komnenian dynasty was not reversed by the Nicaean Empire. While the navy remained active and occasionally successful, reliance on Italian naval power through alliances and diplomacy continued, as exemplified by the Treaty of Nymphaion in 1261. This agreement between Michael VIII Palaiologos and the Republic of Genoa provided Genoese naval support in exchange for commercial privileges. Although it facilitated the recapture of Constantinople that same year, the long-term effects of such policies were detrimental, undermining both Byzantine maritime independence and economic stability.

While Michael VIII Palaiologos had the last significant Byzantine fleet built, it was disbanded by his successor Andronikos II Palaiologos. Later, Andronikos III’s small navy, under the command of the megas doux Alexios Apokaukos, achieved some success against the Genoese.

John VI Kantakouzenos also constructed a small flotilla, but by the end of the 14th century, Byzantium naval power was insignificant and the control of the seas had firmly passed to the Italians and the Turks.

References

  • H. Ahrweiler, Byzance et la mer (Paris, 1966).
  • L. Bréhier, “La marine de Byzance du VIIIe au XIe siècle,” Byzantion 19 (1949), 1-16.
  • F. H. van Doorninck, “Byzantium, Mistress of the Sea: 330-641,” in A History of Seafaring, ed. G. F. Bass (New York-London, 1972), 133-158.
  • E. Malamut, “Les insulaires des Xe-XIIe siècles: marins ou soldats?” JOB 32