The town of Isaccea has been inhabited for thousands of years, as it is one of the few places in all the Lower Danube that can be easily forded and thus an easy link between the Balkans and the steppes of Southern Ukraine and Russia. The Danube was for a long time the border between the Romans, later Byzantines and the “barbarian” migrating tribes in the north, making Isaccea a border town, conquered and held by dozens of different peoples since prehistory.

Roman fortress of Noviodunum known also as the Noviodunum ad Istrum is located about 2 km eastward from Isaccea town in Tulcea County, Romania, on a promontory on the right bank of the Danube, watching the last ford before the Danube Delta. The Noviodunum fort was one of the most important centers of defense system at the Lower Danube. The name of Noviodunum is of Latin-Celtic origin, meaning “New Fort”. The important archaeological site of Noviodunum is situated on the northern edge of Dobrogea, the region which in Romania is bounded by the Black Sea to the east, Bulgaria to the south, and the Danube to the west and north. The Danube now forms the border with the Ukraine in this region, but in the past it has formed the border between the Roman and Byzantine Empires and barbaricum, and between Ottoman dominated Dobrogea and Russian dominated Bessarabia.

Numerous traces of human habitation from the prehistorical era have been found in the area. Jordanes mentions in his annals that : “The abode of the Sclaveni extends from the city of Noviodunum and the lake called Mursianus to the Danaster, and northward as far as the Vistula”. The Noviodunum fort place has been reused during the history by Byzantines and Ottoman Turks, in the Middle Age, as well as in the wars of the 20th century. The Noviodunum site is mentioned in a variety of ancient sources including the Notitia Dignitatum and appears to have been a base for the lower Danube fleet, the Classis Flavia Moesica as well as other military units. The most impressive Noviodunum ruins anyway belong to six centuries of Roman civilization and features the main fortress that consists of an elongated promontory bounded by the Danube on its northern side. Noviodunum was passed under Roman control with the annexation of Thrace in 46 AD, being then attached to the Roman province of Moesia. Noviodunum was part of the Roman province of Scythia Minor in the Late Antiquity where among others, the headquarters of the Classis Flavia Moesica /Danube military fleet/, units of legio V Macedonica, and the Roman Principate, and the main headquarters of the legio I Iovia Scythica were settled. At Noviodunum the tower clearly dominates access to the site across the land bridge from the south. The inside of the Novidium fort area has not been uncovered yet, but a Christian basilica has been identified. Alongside the military installations of Noviodunum was a large subsidiary ‘civil’ settlement, and an extensive cemetery. The civil settlements became municipium during the late 2nd century, surviving on the hostile border until the 7th century. A new and important urban cycle is consuming between the 10th and the 15th centuries.

Archaeological research at the Noviodunum site started in the mid of the 20th century and are still in process. The Noviodunum area enclosed by walls is about 9 ha, but scholars guess that there are two distinct fortifications, dating at least before the 4th century: a military one, the headquarter of the Danube Fleet, and a second fort place which should protect the municipium, at least beginning with the late 2nd century; a city with this status is independent from the military garrison, being usually a pre-existing settlement. Noviodunum did not exist in isolation but was supplied with food and goods from both its local hinterland and the rest of the Roman and Byzantine Empires. Each has left its mark on the site with Roman, Byzantine, Ottoman and 20th century defences overlying each other at this key spot, the last easy crossing of the Danube before the multitude of channels and marshes of the Danube delta. The site of Noviodunum is now a national archaeological reserve, and the subject of several projects.