River Dancers – The Roman Imperial Fleet on the Danube

The Romans decided early to use the Danube as a natural barrier, frontier and a border. In addition, the Danube waters saved lots of energy and money. The Germanic Limes (Limes Germanicus) ended near the city of Regensburg (Germany) on the left (northern) bank of the Danube, protecting the Roman provinces of Germania Inferior and Raetia. The Danube was to become the “water limes” for the provinces further east: Noricum, Pannonia, Moesia and Scythia to the Danube Delta. These new Danube Limes, or Ripa Danuvii, became the longest and biggest structure ever built in Europe. Efforts are now being made to get the ruins of the Danube Limes on the UNESCO World Heritage List. It was protected by the limes road, a typical military road along the southern bank of the river, most of it built under Domitian and Trajan but finally completed under Emperor Caracalla. The early Roman military camps on the river bank were built all the way to the cities, and fortified and walled strongholds and fortresses (castra) were established. Today, more than one hundred Roman settlements along the Danube have been identified. They were added numerous watch towers and signal posts, built within just 2 km. However, it was the Imperial Roman Navy that had the real control over this water border with the unknown, undiscovered areas: marine superpower, consisting during Emperor Diocletian of 64,000 men. Part of it became the famous Danube Fleet (Classis Histria) – the earliest records of it go back to 20 BC‒10 AD. The fleet was divided into three parts: Classis Germanica, Classis Pannonica, and Classis Moesica.

The Pannonian Fleet (Classis Pannonica) operated from its headquarters in Carnuntum (today: east of Vienna, Austria) and Tauronum (today: Zemun, municipality of Belgrade, Serbia) near Singidunum (Belgrade), where the 4th Roman legion was based. The most threatened was the Lower Danube with more than 1,000 km to be defended. This longest part of the water limes was at first defended by two legions, and under Emperor Marcus Aurelius by four legions.

This section of the Danube was where the Flavian Fleet of Moesia (Classis Flavia Moesica) was established and operated from 20 BC to 10 AD. It covered not only the river from the Iron Gates up to the Danube Delta, but also along the northern coast of the Black Sea up to the Crimea (from 41 AD). Flavia, the honorary title, was also given to the Pannonian Fleet in 75 AD by Emperor Vespasian. Its headquarters were originally at Novidunum (literary: “new fortified settlement” on the Danube, today: Isaccea, Tulcea County, Dobruja, Romania). In 85 AD, Domitian moved the headquarters to Sexaginta Prista, the “city of sixty ships” (today: Ruse, Bulgaria). This naval centre, established by Vespasian in late 69 and early 70 AD, was rebuilt and heavily fortified around 250 AD, after the attacks by the Goths, and destroyed in the 6th century by the Avars and Slavic tribes. Other important anchors of this fleet were at Novae (today: 4 km east of Svishtov, Bulgaria), Ulpia Oescus (today: 55 km northwest of Pleven, Bulgaria) and Tomi (today: Constanta, Romania).

The main role of the Danube Fleet ‒ which, in addition to the headquarters had over two dozen ports, marinas and wharfs along the Danube making it a great economic factor ‒ was to guarantee Roman peace (Pax Romana) through border control. It also played a big role in the logistics for the legions, transporting food, weapons and troops. Finally, as was the case during Trajan’s campaigns against the Dacians, they had to support and help the legions during the war.

These disciplined marines of the Classis Histria had an ambitious plan: each kilometre (or rather, Roman mile) of the river had to be checked out once a day. This Herculean work functioned perfectly until 350 AD. Even during the rule of Marcus Aurelius, who had to fight Marcomannic wars several times along the Danube (from 166 AD). The Imperial Roman Navy also crossed the Danube to the north. It defended bridgeheads and toeholds along the northern banks, inspected buffer zones and helped the legions to protect new lime earth walls in province of Dacia.

Rowing, Rowing, Rowing – The Ships of the Roman Naval Fleet

The Danube fleet consisted of a great variety of vessels. The most common one was navis liburna, a small galley, used for patrols, raids and attacks. It was similar to the ancient Greek ship penteconter with 25 oars on each side, a mast and a sail. It could reach a maximum speed of 9 knots (18 km/h). It had a rostrum (naval ram) to enter and sink ships in battles. Armed with two banks of oars, a bireme was 24 metres long and up to 3 metres tall. This type of galley had 120 rowers. Armed with three banks of oars, a trireme had 170 rowers and a deck crew of 30 men. This was a common war ship in the Mediterranean, able to cross up to 120 km a day. The Imperial Navy used even larger vessels: quadriremes and quinqueremes, and even bigger flagships for commanders. These vessels were heavily equipped with ballistae(missile weapons that launched projectiles at distant targets) and catapults.

The favourite of the Romans sailing the Danube (and ancient ship spotters) was this small military vessel ‒ the speedy navis lusoria (“dancing” or “playful” ship). It was perfect for patrols, raids and transport of the troops. It had 30 oarsmen and an auxiliary sail. Just 21 x 2.8 metres, it could navigate even the less deep tributaries of the Danube. These “dancing queens” sailed and ruled the Danube waves and were good for fighting. Emperor Theodosius maintained 90 lusoriae; in 412, 110 of them were used in the war. Students at the University of Regensburg (Germany) proved its mobility with a replica named “Regina” in 2006. They sailed down to Budapest, covering 100 km a day.

Roman navy ships were often decorated with a figurehead (parasemum) and were named after gods (Mars), mythological heroes, (Hercules), geographical maritime features (Oceanus), concept names (Concordia, Pax, Victoria) or after important military events (e.g. Dacicus, to honour the memory of Trajan’s successes in the Dacian Wars).

Sailing the Danube, Protecting the Territories

The Romans used pontoon ships for quick transfers of troops from one bank of the Danube to the other. They used naves cursoriae for the transport of mail and naves iuridica for official VIP visits from Rome. The most common ones were naves agrariensis, used for the transport of foodstuffs, and naves actuariae, shallow-draught vessels with 30 oars.

The navy, of course, protected freight ships and rafts cruising the Danube. These were sometimes moved along the newly installed tow paths. Salt and iron from Noricum, cattle, foodstuffs, cereals, ceramics, gold (from Dacia), wine and olive oil from the Balkan provinces were traded between the East and the West, to and from Rome, and from the North to the South. Sirmium (today: Sremska Mitrovica, Serbia), on the banks of the Sava, was not only the capital of the province and the Empire but also a trading focal point where the North, the South, the West and the East met.

Navy marines spent their pay in the civilian parts of naval city bases, the cabanae (named after simple pubs and brothels for soldiers), increasing the total economic turnover. After their military service was completed, they settled along the Danube.

Sailing through Migrations – The End of the Naval Power

There were some wooden bridges but there were only two stone bridges on the Lower Danube: Trajan’s Bridge and Constantine’s Bridge. Both were dismantled soon after opening in fear of invasions from north and northeast. Author Jordanes called these areas, i.e.. the flatlands of Pannonia that were difficult to defend, “vagina gentium” (“the womb of all nations”) in his major work Getica (551 AD), a description of the early history of the Goths.

It all started when Germanic tribes and Goths beat Roman ships in two attacks around 256 AD. One took place on the Danube. They built their own fleet, raided the cities all the way down to Athens and attacked the Danube fleet. The next shock came in 267–270, with an even bigger invasion. According to the historian Augusta, in late 268 and early 269 more than 2,000 ships with 325,000 men landed on the Thracian shores of the Black Sea to conquer the Roman Balkan provinces. The first big migration could only be stopped by Emperor Claudius II, who defeated the invaders in the Battle of Naissus (today: Niš, Serbia).

Among other things, this led to the final fall of the province of Dacia in 271. In addition, all fortified places along the Danube shrank in size. Fewer inhabitants concentrated in the walled city areas. In some cases, cities were reduced to their amphitheatres, which were turned into fortified castles and last strongholds of Roman defenders.

Classis Moesica remained in function until the start of the 5th century, when the fleet was integrated in the Byzantine Navy of Constantinople. In the Western Roman Empire, which fell in 476 AD, there was no longer an active navy fleet. People had to wait until the 19th century for another fleet similar to that of the ancient Roman fleets. It was the Austro-Hungarian Donaudampfschifffahrtsgesellschaft. The “dancing ships” were spotted again on the Danube in the 20th century but this time they were carrying tourists.

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