Frontiers of the Roman Empire – The Danube Limes (Bulgaria)

Description

The Danube Limes is integral part of the system of the Frontiers of the Roman Empire. The Frontiers of the Roman Empire are the largest single monument built by one of the most influential civilizations in human history, stretching on three continents at a length of more than 7000 km, including and linking together hundreds and even thousands of individual fortified sites and ancillary features.   

In the sense of cultural heritage of world significance, the final goal has always been to have the entire system of the Frontiers of the Roman Empire declared as such. The idea of how to accomplish that has evolved throughout the years. The initial concept of having only one WHS “Frontiers of the Roman Empire” (already inscribed, Ref. No: 430ter), that should include all the national segments has evolved to the idea of having several transnational world heritage sites that will be united by a common framework and will form a cluster named “Frontiers of the Roman Empire”. One of these world heritage sites is namely the Danube Limes. For the Danube Limes, the concept to carry out the nomination in two stages was adopted. The first stage concerns the Western segment consisting of the sites within the territories of Germany, Austria, Slovakia and Hungary, and the second stage – the Eastern segment comprising the sites in Croatia, Serbia, Bulgaria and Romania. The Eastern segment is envisaged to be a major extension to the Western segment that should be the first to be inscribed as a WHS. The division into two segments is due to timetable and management reasons. It is also supported by the clear chronological differences in the evolution and duration of the two sectors.

The frontier along the Danube was gradually established in the 1^st century AD and was strongly fortified after a temporary collapse in the late 3^rd century. The western part, reaching approximately to the Croatian-Serbian border, was abandoned at the fall of the Western Roman Empire by the mid-5^th century, while the Eastern part continued to serve as the frontier of the Eastern Roman Empire until it was given up in the early 7^th century. The presence of many Late Roman and Early Byzantine fortifications, some of which in considerably good state of preservation, is a distinctive characteristic of the Limes on the Lower Danube. It gives it some unique aspects that are not present at any other stretch of the Roman frontiers. Thus the Eastern segment of the Danube Limes as an extension would provide a substantial enrichment and contribution to the Outstanding Universal Value of the Danube Limes as a whole. 

The length of the Danube Limes, considered for nomination by this proposal is approx. 1800 km. The proposal envisages the nomination of more than 130 individual component parts on the territory of four countries (Croatia, Serbia, Bulgaria and Romania). These include: 7 legionary fortresses:  Singidunum, Viminacium, Ratiaria, Oescus, Novae, Durostorum, Troesmis and nearly 120 auxiliary forts and smaller fortifications; civic settlements, cemeteries, production grounds, roads etc., all related to the functioning of the Roman frontier along the Danube.

The province of Moesia started off as a northward extension to that of Macedonia[1]. It received its own governor when Claudius added the Danubian Plain to its territory at the creation of the province of Thrace. By that time, Rome had already for over a century been interfering with regional affairs on both sides of the Lower Danube, but it seems that the Claudian rearrangement first led to the foundation of permanent military bases on the river. Nevertheless, military interventions across the Danube continued, at least as far as the Dnjestr river, over 100 km to the north of the Danube delta. It was only after Dacian incursions in 68/69 and 85/86 from across the Danube that the military infrastructure along the river was considerably extended. Following the latter invasion, the province was divided in a Superior and Inferior part. At the creation of the province of Dacia in 106, the military occupation of the bordering section of the Danube was reduced, whereas the lower course along the Dobrudja was strengthened following the inclusion of the eastern part of the Romanian Plain into the territory of Moesia, but this was soon given up. In the mid-3rd century, the Moesian frontier suffered from invasions of Goths and other peoples, and in 271 the Dacian province was evacuated. Following these events both the provincial structure and the frontier were reorganised. Although barbarian raids persisted, the area more or less survived the collapse of the Western Roman Empire in the 5^th century. As part of the Eastern Roman Empire the Moesian frontier was restored in the first half of the 6^th century, but following invasions of Avars and Slavs heralded the end of the Danube frontier in the early 7^th century. The long survival is a distinctive characteristic of the Moesian frontier. A further remarkable feature is the near absence of fortlets and towers, with the exception of the Iron Gate. Although it cannot be excluded that this is influenced by the state of research, an explanation might be that on this frontier more than elsewhere the opposite river bank was under military control.

From point of view of geography, the Eastern sector of the Danube Limes includes the national segments (in geographic order from left to right) of Croatia, Serbia, Bulgaria and Romania. It starts from the point where the Serbian-Croatian border, which in that part runs along the Danube river, meets the Hungarian border. From that point till Vukovar (Croatia), the Danube flows from north to south[1]. At Vukovar, the river changes to the east due the mountain range Alma Mons/Fruška Gora north of Sirmium/Sremska Mitrovica. In that region the River Tisza, Drava and Sava flow into the Danube. At the confluence of the Sava at Singidunum/Belgrade the outskirts of the southerly mountain ranges start closing in on the Danube. Some 100 km downstream the river flows into the narrow gorges of the Iron Gate. The mouth of the Sava and a westerly entrance to Dacia were occupied by legionary fortresses at Singidunum and Viminacium/Kostolac by 85/86 AD, at the occasion of Domitian’s Dacian War. The Iron Gate itself was supervised by mainly small posts distributed along the more accessible parts, some already installed under Tiberius and Claudius. From the exit of the Iron Gate the Danube took a winding course until Ratiaria/Archar. The dense series of military posts overlooking this stretch were mainly built in the 3^rd and 4^th centuries. Downstream from Ratiaria the Danube follows a relatively straight course until as far as Durostorum/Silistra, between the Wallachian/Romanian Plain to the north and the more elevated Danubian Plain to the south. For much of this c. 400 km long stretch the river has a wide and often twisting channel. The legionary fortresses of Oescus/Gigen, Novae/Svishtov and Durostorum were built at rare spots where the river has a single, narrow bed. The intermediate military posts were often built in high positions with a clear view over the river and the plain beyond. Downstream from Durostorum the Danube takes a northerly course, developing many twisting channels in a wide zone, before bending to the east at Barbosi and creating a delta near Aegysus/Tulca. In this region the military installations were invariably built on the higher grounds along the most easterly river channel.

[1] The following paragraph is taken from: R. Ployer, M. Polak, R. Schmidt, The Frontiers of the Roman Empire. A Thematic Study and proposed World Heritage Nomination Strategy, Vienna/Nijmegen/Munich, 2017, p. 41, 75-6

Name(s) of the component part(s)

Description of the component part(s)

West end at the Timok river mouth, Vidin district – 44°12'48.94"N, 22°40'12.71"E

East end at the city of Silistra, Silistra region – 44° 7'19.75"N, 27°16'39.04"E

The section of the Roman Limes on the territory of modern-day Bulgaria is about 471 km long. It runs along the river Danube – from the fort Dorticum, east of the mouth of the Timakos (Timacus fl.) river (modern Timok River at the Serbian-Bulgarian border), through the provinces of Vidin, Montana, Vratsa, Pleven, Veliko Tarnovo, Ruse, Silistra up to Durostorum (present-day Silistra city; at the Bulgarian-Romanian border). In a wider context this stretch of the frontier is part of the Danube Limes which starts close to the fort of Eining in Bavaria, where the Upper German Raetian Limes ends, and stretches for more than 2800 kilometers all the way down to the Black Sea.

The province of Moesia was established, according to the latest researches, in AD 12. Its eastern part, including section of the Danube Limes, coincides with territories in modern-day northern Bulgaria. In AD 86 it was divided into two new provinces – Moesia Inferior to the east, and Moesia Superior to the west. The Kiabros river (Cebrus) (modern Tsibritsa) marked the border between them.

After the Dacian Wars of Emperor Trajan (AD 101-106) a new province called Dacia was established to the north of the Danube. In the beginning of the reign of Emperor Hadrian the newly conquered territory to the east of the Alutus river (modern Olt in Romania) was abandoned, and the eastern border of Dacia was set along the course of the Alutus. The stretch of the Danube bank downstream to the estuary of the Alutus river ceased to be imperial frontier for more than 150 years.

After the evacuation of the province of Dacia in the reign of Emperor Aurelian (AD 271-275) the Danube marked again the north-eastern border of the Roman Empire. The section of the Danube Limes belonging to modern-day Bulgaria, was used as a water frontier of the province of Moesia Secunda (to the east) within the diocese of Thracia and of Dacia Ripensis (to the west) within the diocese of Dacia. The Asamus river (modern Osam) was the borderline, separating not only the two dioceses, but also the two prefectures.

Already by the turn of the 3^rd century a campaign of massive reconstruction of the Lower Danube limes was initiated by the central Roman administration. It was continued and systematically carried on throughout the first three quarters of the 4^th century. The fortifications were totally rebuilt according to a new pattern. Some of them were relocated to places offering better natural defense. Many new fortifications of different type and size appeared.

The infrastructure of the Late Roman limes on the Lower Danube was badly damaged by the Gothic and Hunnic invasions in the last quarter of the 4^th and the first half of the 5^th century. Therefore, a large-scale new reconstruction was needed and it was initiated by Emperor Anastasius in the late 5^th century. It was carried out in several stages until the end of the rule of Emperor Justinian I. Minor repairs were made also in the last decades of the 6^th century. During the reign of Emperor Heraclius, the Roman Empire lost control over the Lower Danube provinces and the limes stopped functioning.

On its abandonment quite some fortification elements were reused during the Middle Ages and survived well preserved into present days.

The Roman frontier system in Bulgaria consisted of a chain of fortifications along the south bank of the river Danube using the river as an additional obstacle and as a communication, supply and trade route. Along the course of the river line lay four legionary fortresses (Ratiaria, Oescus, Novae and Durostorum) and many forts and watch-towers, 46 of which have been precisely identified on the ground to this day. The written sources give the names of even more fortified sites, which must have lain along the course of the Danube but are still not recognized.

The Limes road linked the individual military installations and other ancillary features. Quite often along a natural boundary, the Limes road runs well behind the course of the river, dictated by the terrain. Watch-towers and fortlets and sometimes also forts, are connected to the Limes road by secondary roads. The Limes road, which is often not easily identifiable in woods, heavily agricultural or densely populated areas, is best preserved between the villages of Dolni Vadin and Baykal, to the east of the town of Nikopol and between the villages of Vardim and Krivina. It might well be recognized on satellite photos in a few more places.

Besides the fortresses, forts and fortlets also some civil settlements, cemeteries and elements of the military infrastructure such as production grounds (stone quarries, lime kilns, etc.) and roads may be referred to the Roman frontier system. 

The settings of the Roman frontier military installations have been influenced by the landscape on both sides of the Danube as a geographical feature as well as by the wish to control the main ancient trade routes and river fords. The landscape the Roman army had to face was dominated by the high and steep Danube bank in some sectors or vast flooded riverside plains in others, as well as the mouths of many rivers flowing into the Danube like Archar, Lom, Tsibritsa, Ogosta, Iskar, Vit, Osam, Yantra. Those geographical conditions determined the location of the frontier installations as well as the deployment of specific types of troops. The legionary fortresses and the bigger auxiliary forts were regularly spaced along the river bank, at a distance of 15-20 km from each other. They were generally situated by the mouths of the right Danubian tributaries, thus blocking the access of invaders into the province along the most convenient natural routes. The minor fortifications lay between the bigger ones, ensuring thorough control of the frontier line and visual communication between the components of the defense system.

In the sense of cultural heritage, the Bulgarian section of the Danube Limes belongs to the Eastern Sector of the Danube Limes, which includes also the national sections of Croatia, Serbia and Romania. The Western segment of the Danube Limes includes the national sections of Germany, Austria, Hungary and Slovakia. The cultural heritage site “Danube Limes” as a whole is an inseparable part of the larger system of the Frontiers of the Roman Empire. It is therefore related to the existing World Heritage property “Frontiers of the Roman Empire” (Ref. No: 430ter), consisting of Hadrian's Wall, the Antonine Wall (UK) and the Upper German Raetian Limes (Germany). According to “The Frontiers of the Roman Empire. A Thematic Study and proposed World Heritage Nomination Strategy”, “… European frontiers, not covered by the current property, should be nominated as three sections: The Lower German (i.e. Lower Rhine) frontier; the Danube frontier; the frontier of the Roman province of Dacia. These sections would constitute three separate World Heritage properties, beside the existing serial World Heritage property. The four single properties would be joined under a common framework “Frontiers of the Roman Empire” …”

The national component part proposed by Bulgaria encompasses both the best known examples of the still existing and well-preserved Roman fortresses, forts and watch towers along the Danube River bank as well as the additional features according to the Koblenz Declaration of the Bratislava Group including: civil towns and settlements, cemeteries adjacent to the military fortifications and elements of the military infrastructure (See List of sites as Annex 1). The river itself and the temporary fortifications are not included in this World Heritage proposal. Over the past 2000 years the river bed has changed by natural processes or by human activity. Due to flooding and erosion some sites on the lower grounds have been partly or completely destroyed by the river. In the 20^th century the Danube river underwent some regulatory measures, which did not help to preserve the monuments. However, quite a lot of sites still have substantial remains both above and below the ground. All sites in question (as listed in the Annex 1) are scheduled and protected by the regulations of The Cultural Heritage Act of 2009.

Justification of Outstanding Universal Value

Criterion (ii): The extant remains of the Frontiers of the Roman Empire – The Danube Limes constitute significant elements of the Roman Frontiers present in Europe. With its legionary fortresses, forts, fortlets, watchtowers, linked infrastructure and civilian architecture it exhibits an important interchange of human and cultural values at the apogee of the Roman Empire, through the development of Roman military architecture, extending the technical knowledge of construction and management to the very edges of the Empire. It reflects the imposition of a complex frontier system on the existing societies of the northern part of the Roman Empire, introducing for the first time military installations and related civilian settlements, linked to an extensive supporting network based on the river Danube. The frontier did not constitute an impregnable barrier, but controlled and allowed the movement of peoples: not only the military units, but also civilians and merchants. Hence, it triggered the exchange of cultural values through movement of soldiers and civilians from different nations. The entailed profound changes and developments in terms of settlement patterns, architecture and landscape design and spatial organization.

Criterion (iii): The property Frontiers of the Roman Empire – The Danube Limes has an extraordinarily high cultural value as it shows the interaction of occupying force with local people and circumstances. It bears an exceptional testimony to the maximum extension of the power of the Roman Empire through the consolidation of its northern frontiers and thus constitutes a physical manifestation of Roman imperial policy. It illustrates the Roman Empire’s ambition to dominate the world in order to establish its law and way of life there in a long-term perspective. It witnesses Roman colonization in the respective territories, the spread of roman culture and its different traditions – military, engineering, architecture, religion, management and politics – and the large number of human settlements associated with the defences, which contribute to an understanding of how soldiers and their families lived in this part of the Roman Empire. The property also adds some specific features to the variation and evolution of the military strategies applied by the Roman Empire to control external “barbarian” societies.

Criterion (iv): The Lower Danube Limes is an exceptional example among the other European frontiers as being the longest lasting amongst them. It brings testimony for a cultural and technological development throughout six centuries. It demonstrates the ability of the Roman Empire and its later Eastern successor to adapt and make efficient the same borderline to the evolving means and conditions of the warfare throughout Antiquity. It is an outstanding example of functional and spatial continuity of a complex system of military facilities, roads and infrastructure that originate and evolve in symbiosis with the natural landscape. The evolution of the concepts behind the shape of the military architecture could be traced by exploring the ruins preserved along the Lower Danube: from the classical early examples of regularly shaped and mostly standardized forts to the unique end ingenious layouts of the defensive structures in the Late Antiquity. 

Statements of authenticity and/or integrity

The section of the Danube Limes on modern Bulgarian territory survives as a chain of fortified sites (fortresses, forts and fortlets, watch-towers; Limes road) and other Roman military infrastructure (roads, stone quarries, production complexes), all organically linked to the landscape along the Danube. Especially the architectural monuments of the late Roman defence system are still a very visible testimony to the power and might of the Roman state and the extent of the Roman Empire. The main outline of the planning concept of Roman forts and military camps still survives in the street grid and the general plans of several modern towns and settlements, such as Vidin, Lom, Dolni Tsibar, Ostrov.

Many fortifications (approximately 50%) are partly or completely covered by medieval or modern settlements. Agriculture, modern construction and other kinds of interventions have disturbed and/or transformed the Roman remains in nearly all of the proposed World Heritage sites. However, the preserved remains are a bright testimony to the overall border Roman military protection system known as the Roman Limes. Many excavations have demonstrated that remains of the Limes monuments have survived remarkably well below ground even in settled or urban areas. There are still many invisible, undisturbed and uncovered elements of the property in nearly all the Limes sites. The visible parts of certain sites (in Vidin, Gigen, Svishtov, Ruse, Tutrakan, Silistra) are kept in good condition, cared for by the local or regional governments and are scheduled under The Cultural Heritage Act.

The Limes road could be partly identified by aerial survey and archaeological investigations between the villages of Dolni Vadin and Baykal, to the east of the town of Nikopol, between the villages of Vardim and Krivina, in the vicinity of the villages of Pirgovo, Marten and Popina.

Justification of the selection of the component part(s) in relation to the future nomination as a whole

The Roman frontier line in modern Bulgaria is part of the whole imperial defence system along the river Danube. The most important characteristics of this section are the gradual expansion of the Roman rule downstream the Danube river and the specific organization of the territory along the border line throughout the time of Roman domination, with many drastic changes from administrative, economic and military point of view. The very appearance of the defence infrastructure along the Lower Danube Roman limes reveals many peculiarities compared to those along the Rhine end the upper and middle courses of the Danube. The Roman army and the fortification system of the Danube Limes in Bulgaria played a crucial role and experienced several major events which determined the policy and history of the whole Roman Empire, such as the Costoboci invasion in c. AD 170, the Gothic invasions in the mid-3^rd century and in the last quarter of the 4^th century, the Hunnic invasions in the first quarter of the 5^th century, and the crucial wave of Avar-Slav invasions in the late-6^th and early-7^th century.

The Danube Limes in Bulgaria represents also an excellent example of the influence of the Roman domination on the economic and social development of a large community and territory between the Balkan Mountain chain and the Danube river. Beside the already existing interchange in north-south direction along the ancient trade routes with the population and territories north of the river Danube, the Roman army established and supported an intense cultural exchange between the western and eastern parts of Europe by building a secure corridor and an international transport route north of the Balkan Mountain chain with additional infrastructure to control this territory. Therefore, the fortifications and the civil settlement structures that developed around the forts often represent a two-folded character combining characteristic elements from western and eastern Roman provinces. The linear defence system was created gradually, in several particular stages. Its establishing began in the first quarter of the 1st century AD from the west, and went on downstream the Danube through the 1^st and the beginning of the 2^nd century AD. In the Late Antiquity the Roman borderline of the provinces Moesia and Thracia in modern Bulgaria shared a similar military history with the neighbouring Danube Limes provinces to the West (in modern Serbia) and East (in modern Romania), with building of a much more elaborate defence system.

The establishment and the structure of the military installations of the Danube Limes in the sector belonging to modern Bulgaria clearly demonstrate the exceptional ability of the Roman army to adjust its demarcation/control/defence system to the individual geographical and demographical preconditions. This can be clearly demonstrated by the different system of frontier installations and the deployment of troops (cavalry, infantry and mixed units) all along the Bulgarian section of the Danube Limes. The still existing fortifications are among the best and highest preserved examples of late Roman military architecture throughout the Empire. The rest of towers, gates and ramparts represent outstanding examples of the technological development of the Roman military architecture and frontier defence.

Comparison with other similar properties

The Frontiers of the Roman Empire – The Danube Limes differs from the already nominated and inscribed sectors of the Frontiers of the Roman Empire (Ref. No 430ter). The most obvious and fundamental difference in the case of the Danube Limes is that the river itself is the demarcation line and not an artificial barrier, as it is in the mentioned WHS. There are main structural differences in river frontiers compared to land frontiers. Part of the very essence of a land frontier system is that an artificial barrier with its structural details (walls, palisades, rampart/ditches) forms a continuous line in the landscape and provides the necessary link between individual monuments (watch-towers, fortlets, forts). This can be demonstrated through and seen in the already existing WHS “Frontiers of the Roman Empire” (including Hadrian’s Wall, the Antonine Wall and the Upper German Raetian Limes), where the relationship between the individual frontier elements is clearly visible.

The Roman Empire has other river frontiers as well – on the Rhine and Euphrates, but the Danube Limes differs from them too. The Limes on the Lower Danube on other hand demonstrates both similarities and substantial differences with the frontiers of the Roman Empire on the Rhine or on the Upper and Middle Danube.

All Roman river frontiers such as the Danube Limes lack these most obvious connecting element(s). Although the rivers form a linear obstacle, which connects the individual monuments, the frontier line and the linearity of the fortification system itself is less easy to define and to present. Forts along the Rhine and Danube river frontiers are between 10 to 30 km apart, and inter-visibility often does not exist. Over the last 2000 years the river beds changed in some areas. Because of these changes and floods many sites on the lower grounds were partly or completely destroyed by the water. This also affected some military sites on the Danube Limes in Bulgaria, such as Yasen, Dolni Vadin (Valeriana), Kozloduj (Zonus and Regianum), Belene (Dimum), Ryahovo (Appiaria). In the 20th century rivers underwent certain regulatory measures, which did not help to preserve the monuments situated close to the water line. But quite a lot of these archaeological sites were detected and investigated through those activities. Another threat is the water power stations with their dams and reservoirs. When power stations system Djerdap was built in Serbia and Romania during the 80-ies of the last century, a long stretch of the Roman frontier, e.g. forts, fortlets, watch-towers and the road through the Iron Gate were flooded and are not visible any longer.

A distinctive feature of the river Rhine and Danube frontiers are chains of watch-towers along one side of the river course and bridgehead fortifications on the other side. Watch-towers, the intermediate elements in the archaeological landscape, are not so easy to detect along river frontiers. Those of the earlier Roman Empire were mainly constructed of timber. No example of them is known in Bulgaria until present. But new research results on the Lower Rhine Limes in the Netherlands, where a longer section of the earliest frontier system around AD 20-40 was investigated during rescue excavations in the area around Woerden, clearly demonstrated that wooden watch-towers were a distinct element of the borderline. Late Roman watch-towers are easier to discern because of their massive stone and stone-brick construction. More than 200 watch-towers, mostly stone towers, are recorded along the Danube banks, the most of them in Hungary, which form a very tight defence system. It can be assumed that similar systems existed on the other Danube frontier sections too. Several examples of such late Roman watch-towers are situated in the area of Pokrayna, Oryahovo and Batin and are included in the actual nomination.

Although there are no clearly identified bridgehead fortifications in Bulgaria, there are such sites known for example in Iža in Slovakia or the fort of Dierna in Serbia. Most of them were constructed when Roman politics caused advances of the army into Barbarian territory. In late Roman times more bridgeheads such as Contra Aquincum (Budapest) in Hungary were established to control, and more so to protect the crossing points and the traffic on the river itself. Such military installations were heavily fortified and several of them survived quite well on the left side of the Danube in Hungary, Serbia and Romania.

As a summary, the long survival is probably the most distinctive characteristic of the Moesian frontier. It survived the frontiers of Raetia, Noricum and Pannonia by more than a century as part of the Eastern Roman Empire. A further remarkable feature is the near absence of fortlets and towers, with the exception of the Iron Gate. Although it cannot be excluded that this is influenced by the state of research, an explanation might be that on this frontier more than elsewhere the opposite river bank was under military control. Another distinctive feature of the section is the remarkable survival of Roman frontier architecture, especially from the Late Roman and Early Byzantine periods.