Oescus, the Roman Colony on the Danube near Gigen
Oescus, also called Colonia Ulpia Oescus, was a major Roman fortress and city on the Danube, beside the village of Gigen in northern Bulgaria, north-west of Pleven. Legions, a colony of veterans, temples, baths and a forum all stood here. It is one of the largest and longest-studied ancient cities of the Lower Danube, and a rewarding detour for anyone interested in the Roman frontier.
In 328 an emperor came here to open the longest stone bridge of the ancient world. In 2020 diggers found a great hall lined with 14 types of rare marble, possibly built for his visit.
The history of Oescus
The town takes its name from the river Oescus, today the Iskar, a word that probably meant “water” in the local Thracian dialect. The geographer Ptolemy called it a city of the Triballi, a tribe of north-western Bulgaria, and traces of the late Bronze Age and the Iron Age have been found on the spot. Under Rome it began as a military base on the Danube frontier, the Limes. The Fifth Macedonian Legion kept a fortress here on and off, left in 62 CE for the war in Armenia, fought in the Jewish war, and came back in 71.
In the early second century, after Trajan's victory over the Dacians, Oescus was raised to the rank of colony, the highest status a Roman provincial town could hold. It took the name Ulpia from the emperor's family name, Ulpius, and was built over the old legionary camp. Veterans settled nearby. The city made jewellery, bronze statuettes, glass and pottery, and housed one of the biggest sculpture workshops of the region. Its forum was unusually grand, with four temples: Jupiter, Juno and Minerva on the south side, and Fortuna, protector of the city, on the north.
After the Romans gave up Dacia in 271, troops pulled back across the river into Oescus. A second fortress, called Oescus II, enlarged the walled area by roughly ten hectares, an aqueduct brought fresh water from springs 20 km away, and a stone wall guarded the town against raiders and Danube floods. On 5 July 328 the emperor Constantine the Great came in person to open and consecrate his bridge to Sucidava on the northern bank, about 2.5 km long and the largest river bridge of antiquity. In 343 a bishop of Oescus took part in the Council of Serdica.
The late city did not survive the turmoil of the migration age. The Huns destroyed it in the fifth century, and Emperor Justinian I rebuilt its defensive wall in an attempt to make it a stronghold of the Danube defences. The Avar invasions of the late sixth century ended those efforts. A large basilica of the fifth and sixth centuries, with rich decoration and a well-preserved mosaic floor, belongs to this last Roman chapter.
Life returned between the tenth and fourteenth centuries, when a Bulgarian village stood among the ruins; a small cross-domed church was even built over the remains of the temple of Fortuna. Excavations began in 1904 under Vaclav Dobruski and have continued ever since. In 2020 archaeologists found that the aula regia, or great hall, had been decorated with 14 kinds of rare multicoloured marble. Its fourth-century date has led to the suggestion that it was built for Constantine's visit in 328.
Curious facts about Oescus
- The name comes from the river Oescus, today the Iskar, and probably meant “water” in Thracian.
- Constantine's Bridge to Sucidava was about 2.5 km long and 5.7 m wide, the largest river bridge in ancient times, and the emperor opened it personally on 5 July 328.
- Its forum was framed by four temples, which made Oescus one of the few cities of the whole Roman Empire with such a layout.
- The great hall found in 2020 was clad in 14 types of rare multicoloured marble, and its date suggests it may have been built for Constantine's visit.
- A 3rd-century mosaic known as “The Achaeans”, found in 1948, is now shown in the Regional Historical Museum in Pleven.
- A statue of the goddess Fortuna from the site is displayed in the National Archaeological Museum in Sofia, and Oescus Island in Antarctica is named after the city.
Tours near Oescus
Experiences in the area that you can book online with Viator:
Visiting Oescus: what to see
- The ruins lie beside the village of Gigen. Visible remains include the main gate, administrative buildings, a civil basilica, three public baths, a well-preserved Roman road, temples, workshops and a necropolis.
- Parts of the defensive wall of the legionary fortress can still be seen, and the walled city has the shape of an irregular pentagon.
- The remains of Constantine's Bridge can only be seen from the northern bank of the Danube, not from the Bulgarian side.
- Many finds are in museums rather than on site: the mosaic in Pleven and the Fortuna statue in Sofia. Check the current opening hours before you go.
- Excavation is still going on, so some areas may be fenced off or look unfinished.
Opening hours, access and conditions can change. Check before you go.
Map: where Oescus is
Photos of Oescus
Questions
What is Oescus?
Oescus, or Colonia Ulpia Oescus, was an important Roman fortress and city on the Danube in the province of Moesia, beside today's village of Gigen in Pleven Province.
Where is Oescus and how do I find it?
The ruins lie at the edge of the village of Gigen, north-west of the city of Pleven, not far from where the Iskar flows into the Danube.
What was Constantine's Bridge at Oescus?
It was a stone bridge, about 2.5 km long, linking Oescus with Sucidava on the northern bank. Constantine the Great opened it on 5 July 328.
What can you see at the Oescus ruins today?
Sources list a main gate, administrative buildings, a civil basilica, three baths, a preserved road, temples, a necropolis, defensive walls, workshops and a forum.
Why was the Roman city abandoned?
The Huns destroyed it in the fifth century, and Justinian's rebuilding was stopped by the Avar invasions of the late sixth century.
Where are the finds from Oescus kept?
The mosaic “The Achaeans” is in the Regional Historical Museum in Pleven, and a statue of Fortuna is in the National Archaeological Museum in Sofia.
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