Frontiers of the Roman Empire – The Danube Limes (Serbia)
Permanent Delegation of Serbia to UNESCO
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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; civil settlements, cemeteries, production complexes, 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 Macedonia4. It received its own governor when Claudius added the Danubian Plain to its territory at the creation of the province of Dacia. 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 to Superior and Inferior parts. At the creation of the province of Dacia in 106, the military occupation of the bordering section along 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, this line of defence survived collapse of the Western Roman Empire in the 5th century. As part of the Eastern Roman Empire the Moesian frontier was restored in the first half of the 6th century but following invasions of Avars and Slavs heralded the end of the Danube frontier in the early 7th century.
The defensive system of the frontier consisted of a chain of fortifications along the Danube River right/south bank. The Danube itself was the primary line of defense. The Second line were several river fleets (classis Pannonica and classis Histrica). These were attached to the main strongholds along the frontier. The army units supported the fleets whenever it was possible. The river was, as still is, a major communication route for both the military and civilian transport and supply. The frontier road network was built by the Roman legions themselves.
The organization of the limes was highly influenced by the natural land configuration. The Limes road linked the individual military installations and other ancillary facilities. Quite often along a natural border, the frontier road runs well behind the course of the river, dictated by the terrain. The watchtowers and fortlets and sometimes forts, were connected to the supra-regional frontier road with the smaller ones. Besides the fortresses, forts and fortlets, there were civil settlements and cemeteries. The legionary forts (Singidunum and Viminacium) were located in a flat open area of central Serbia, suitable for large scale military operations. In the Iron Gates, the terrain narrows the area along the river to the level that the road had to be cut into the rock or be built over the river itself. This was a region that was garrisoned only by smaller units up to the rank of cohorts. Downstream from Kladovo, the valley widens up again and bigger auxiliary forts are located on strategic points.
The river crossings were of strategic importance for any kind of military operations or potential trade with the barbarians. One of the crossings was by Singidunum and Taurunum at the confluence of the Sava and the Danube rivers. The second strategic crossing was below the Lederata fort (present day Ram) over Sapaja Island. The best-known crossing was the Trajan’s bridge (Pons Traiani) near Kladovo at Kostol (Pontes fort – the “Bridges”).
Navigation along the river was of the utmost strategic importance. The river boats enabled fast transport of troops and goods, continuous supply of units and provided the first line of defense when confronting barbarian intrusions. The main ports were established in Taurunum, Singidunum, Margum, Viminacium, Diana, Aquae and Egeta and by the several smaller fortifications with mainly support and supply roles. From point of view of geography, the Easter 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 south5. 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 (Stari Kostolac) during Flavian period, as preparations for the upcoming Dacian Wars. 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 3rd and 4th 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.
4 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, 90-91
5 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
Description of the component part(s)
- Begeč (Castellum Onagrinum), Bridgehead and auxiliary fort, Novi Sad Municipality Archaeological excavations of the site known as “Kuva”, conducted from 1967 to 1975, uncovered a Roman military fortification – castellum Onagrinum. This fort is a Roman bridgehead to Barbaricum as it is located on the left bank of Danube. The remains of the tower with the semi-circular foundations have been explored. The northern rampart has also been determined. Massive footing slabs by the Danube bank indicate the existence of a pier. The fortification was erected in the 4th century, as indicated by Roman coins and pottery, found opposite to the fortification Malata Bonnonia, on the left bank of the Danube.
- Petrovaradin (Cusum), auxiliary fort, City of Novi Sad, Petrovaradin Municipality
The medieval fortress of Petrovaradin was erected at the place of the Cusum, Roman fort, at a high rock rising above the Danube right bank. At the foot of the Petrovaradin Tower a native settlement with early roman import was documented. Rescue archaeological excavations of the plateau of the Upper Tower conducted in 2001 and 2002 established that parts of the walls of the Roman fort were built above prehistoric earthen ramparts. A rampart tower with a gateway stood above the Danube bank. It has been established that in the space between today’s buildings, known as Long and Simple Barracks, there was a long wooden portico, covered with roof tiles. The portico was destroyed by fire in the late 4th century. The roof tiles bore seals of several Pannonian brickyards.
- Čortanovci, Mihaljevačka šuma (Ad Herculае), auxiliary fort, Inđija Municipality
The Late Roman fort stands in the area of the village Čortanovci, on the Danube’s right bank, in Mihaljevačka šuma (Mihaljevačka forest), on the “Prosjanice” site. Trench excavations conducted in 1956 and in 1961–1962 at the south-eastern part of the fortification, recorded a circular tower 13 m in diameter with walls 1.20 m thick, preserved to the height of about 3 m. The tower was built of stone with several courses of brick. The fort was erected in the 4th century. The ancient name of the fortification is not ultimately proven – it might have been Ad Herculae / Ad Herculem or Castra Herculae / castra Herculis.
- Slankamen (Acumincum), auxiliary fort, Inđija Municipality
The remains of a medieval city dominate the plateau of a protruding loess outcrop on the very bank of the Danube, at the “Gradina” site. Systematic excavations from 1955 to 1957 established that medieval walls extended from the Roman walls, following their direction. Two phases of the Roman settlement were established: an early Roman settlement formed at the time of Flavius and a fortified Roman settlement with massive walls bound with mortar, most often accompanied by finds dated to the 4th century. The position and the finds indicate that the Roman fortification with civil settlement Acumincum stood here and that Cuneus equitum Constantium and Equites sagittarii were stationed here.
- Surduk (Rittium), auxiliary fort, Stara Pazova Municipality
At the elevated bank of the Danube, at the “Gradina” site reconnaissance and minor trenching in 1955 uncovered the remains of an early Roman settlement with imperial coins dated to the 1st century, as well as the remains of a military camp and brick built tombs dated to the 2nd–4th centuries. Here, at the military stronghold Rittium Equites Dalmatae and Cohors II Asturum were stationed. Altars and statuettes, as well as other small finds suggest that Rittium was also a religious center.
- Zemun (Taurunum), Roman cemetery, City of Belgrade, Zemun Municipality
The remains of a Roman cemetery were identified at beneath the Millennium tower of “Gardoš“, and the slopes around it. According to the sources and itineraries fortification and strong river port guarding the confluence of Sava and Danube rivers are located here. According to excavated graves cemetery can be dated into 3rd and 4th century. Smaller units of the legio VII Claudia were posted in the fort. Military port and the home base of the Pannonian fleet - Classis Flavia Pannonica was documented in multiple sources that span throughout Roman occupation. Although all over Zemun small finds suggest long Roman occupation neither fort nor port are identified with certainty – therefore property for nomination is limited only to the documented cemetery.
- Belgrade (Singidunum – Legionary fortress), Belgrade fortress and Belgrade City Library, City of Belgrade, Stari Grad Municipality
The site where modern Belgrade lies was very important for the defense of the Roman Empire after it established its frontier on the Danube in the 1st century AD. There are indications that legions IIII Scythica and V Macedonica were periodically stationed at Singidunum as early as the first half of the 1st century. With the military and administrative consolidation in the area of the Danube frontier, Singidunum became the base of the Legio IIII Flavia, stationed there until the end of the Roman rule. The remains of a Roman Legionary fortress of the Legio IIII Flavia were discovered and partially excavated during the years of excavations in the Belgrade Fortress area. Its ramparts, the oldest vestige of any fortification on the site were poorly preserved. As a result, little is known about the earliest phase of the Roman fortifications. It has been ascertained, however, that the fortress was located in the Belgrade fortress Upper Town area and in a section of Kalemegdan Park adjacent to Pariska Street, as well as on the nearby zone along the opposite side of the street. Porta Decumana, southeast gate, was excavated and presented today in the Belgrade City Library. Fortress was irregular rectangular in plan (560 m long by 330–380 m wide), the walled enclosure covering an area of 20 ha. In addition to this main hilltop fortress, the riverside was defended by another two ramparts running down the Danube facing slope. Singidunum as the frontier stronghold reached its peak in the 2nd and the 3rd centuries. During the last 70 years, research of legionary fortress in Singidunum gave various results. Although it was excavated on different occasions during such a long time, only some parts of its layout have been determined. The main problem of proper research of legionary fortress in Singidunum lies in the fact that large parts were destroyed by medieval and latter fortifications. Large parts of praetentura around via principalis, as well as principia were completely destroyed by the bastion fortifications in 17th and 18th centuries.
According to various archaeological excavations one can define the precise length of the lateral side, but not the precise width of fortress. Positions of NW, NE and SE rampart walls have been determined so far, but position of SW wall remains doubtful. With the length of 568 meters Singidunum fortress is similar to fortresses erected during the second half of the 2nd century. According to the find of last barrack block in the most south-western part of raetentura, we can say that fortification width was more than 400 meters. Since that erection of bastion fortifications has destroyed most of SW side, and since there is huge difference in ground levels, where steep slope (30 meters height difference) hits the river shore (the Sava River), it is difficult even to presume the position of SW wall. Find of wall oriented in NS direction refers to much later period when barracks were not in function. Gates on NW and SE side have been excavated with various results. NW gate (porta praetoria) had two inner towers and narrow passage of just 3 meters. On the opposite side porta decumana with inner towers had much larger passage of 12 meters (28.3 m when outer sides of the towers are measured). Only systematic research of fortress interior was conducted on the SW side, where four rows of legionary barracks were found. The walls were made of rough stone connected with lime mortar. The barracks were divided into contuberniae with veranda on the street side. Remains of supporting pillar stones, and channels were found in the space between veranda and streets.
- Belgrade (Singidunum – Roman city), Studentski Park, City of Belgrade, Stari Grad Municipality
Municipium and later colonia occupy the central part of modern Belgrade. Civil settlement, as well as cemeteries around it, lies below the very centre of Belgrade, with Studentski Park among the rare zones for possibility of presentation or future large-scale excavation. In the civil settlement area, mainly rescue excavations have yielded some results regarding city’s architecture, but not to the extent to understand completely the urban layout, possible position of the forum, and other urban elements. Two streets oriented in the NW-SE direction show that the establishment of 2nd – 4th century settlement was influenced by the orientation of the castra. Most of the excavated structures show the same orientation. Inhabited area was roughly 35-40 ha, stretching on both sides of the central reef on Belgrade hill. Necropolis dated in the period of 2nd – 3rd century occupied area along the road to Viminacium in the line of 1.6 km. Civil settlement of Singidunum got its municipal status in the period of Hadrian. On the NW riverside, by the confluence, on few occasions’ buildings dated in 2nd and 3rd centuries were discovered. Besides others, speleaum dedicated to Mithra. According to numerous military equipment finds, Lower Town area has strong military context, perhaps as NW canabae. In the late antiquity this area was protected by one of the side walls running from NW tower along the slope towards the river.
- Višnjica (Ad Octavum), auxiliary fort, City of Belgrade, Palilula Municipality
During the reign of the Byzantine Emperor Justinian (527-565 AD), a fort known as castrum Ad Octavum was erected on the right bank of Danube, about 10 km downstream of Singidunum. The fortification is located on the site "Gradina", on an elevated plateau 2 km away from the modern village of Višnjica. This fort was known from historical sources; Procopius mentions the fortress Octavum on the eighth Roman mile from Singidunum (about 11.8 km), among the fortifications restored or built on the limes by Emperor Justinian.
The fortification at “Gradina” elevation is rectangular in shape, approximately 180 x 100 m in size, with ramparts made of large ashlars, crushed stone and bricks. Preliminary excavations and survey showed massive bulwarks built in flagstone from the local quarry. Remains of a circular tower were discovered on the south side, and a wide rampart from the northeast corner was traced in the direction of the Danube. Small finds suggest a longer use of this space, from late antiquity to the late Middle Ages. West of the fort, a necropolis with two burial horizons was discovered - Late Antique and Early Byzantine. This may point to a slightly different date and the possibility that the fort was built in late antiquity and restored in the 6th century.
Today, almost the entire area of the fort is underground and covered with forest - only a couple of stone walls are still visible.
- Ritopek (Tricornium), auxiliary fort, City of Belgrade, Grocka Municipality
The remains of the Castra Tricornia have been observed and documented in the 19th century. In the Ritopek area, numerous finds have been discovered dating from the 1st – 4th century period. There are indications of fortification right beneath the hill with modern cemetery that preceded late high ground fortlet. There is a small settlement that was formed along the fortification and the cemetery. Limes Geophysical Survey project is in progress on the site.
- Brestovik, Tomb of a high-ranking officer or dignitary, City of Belgrade, Grocka Municipality
In the village of Brestovik, situated at the edge of the Belgrade City territory, а large wall painted family tomb was discovered in 1895 by accident. In the Roman times, the tomb was located along the road from Singidunum to Viminacium, between Castra Tricornia (today Ritopek) and Ad Sextum Miliare (today Grocka). Along this communication, many wealthy villas with necropolises used to be built, from the 1st to the 4th century AD. The Brestovik tomb itself was dated into the period of late 3rd or early 4th century.
The tomb consists of three rooms. The vaulted burial chamber with three burial places was fully decorated with wall paintings. Middle room flanked by two apses was wall-painted but also decorated with stone sculptures of lions and genii. The marble statue portraying high officer or even one of the tetrarchs as some researchers suggested was found in the room. The entrance room – vestibule had four columns bearing tympanum. A long dromos cut into the terrain slope led to the rooms.
Wall painting of the tomb belongs to some of the finest examples of late antique art, still preserved in situ. The beams presented on the walls were painted in a manner that suggests they hold the heavenly vault above. Painted motifs on the walls include geometric, vegetative and zoomorphic motifs, while the vault painting imitated coffered ceiling, using vegetative motifs.
The architectural composition of the tomb, in combination with sculptures and wall paintings, testify that it was the burial place of a high-ranking Roman, probably military commander and his family. However, popular belief in today’s local Christian community, developed according to some early Christian sources, is that the martyrs of Singidunum, Hermylus and Stratonicus, were buried inside. The tomb from Brestovik is a unique example of burial on the frontier in this sector of the Danube Limes, whose architecture, but also painting, as one of the best-preserved in situ examples of the Roman provincial funerary art, can be connected to the analogous examples in the Near East and North Africa.
- Seone (Aureus Mons), auxiliary fort, Smederevo Municipality
Aureus Mons is a Roman fort with adjacent settlement that used to be in the Seona area. Roughly, it can be dated to a period between the 1st and the 4th centuries. The fortress is mentioned by a Roman historian Eutropius who wrote that the emperor Probus (276–282) let the soldiers to grow vine in the Aureus Mons area. The archaeological investigations published in 1963 designated the remains of a Roman fortification, dimensions of 150 x 130 paces, on the Seona stream left bank, directly before its Danube confluence.
- Dubravica, Orašje (Margum), City and fort, Smederevo Municipality
Margum is located on the Morava River right bank, near its Danube confluence. The “Orašje” site holds the remains of a Roman fortification. Archaeological excavations were conducted between 1947 and 1949 on a limited area and three phases were established in the 1st – 4th centuries period. The sources mention here location of the strong river fleet base. Civil settlement formed around the fortification. Margum flourished in 2nd century and even gained a status of municipium (Municipium Aurelium Augustum Margum). During late antiquity one of the command posts of the Danube fleet was stationed here - Classis Stradensis et Germensis as it was documented in Notitia Dignitatum. Excavations and LiDAR surveying in the last decade revealed new architectural features, as well as part of necropolis of Roman Margum.
- Stari Kostolac (Viminacium legionary fortress and city), City of Požarevac, Kostolac Municipality
Viminacium was the most important legionary fortress and city in the province Moesia Superior (in late antiquity province Moesia Prima). It was the capital, administrative, religious, military and trade center. The area covered by this ancient Roman city and legionary fortress is over 450 hectares of the wider city region and 200 hectares of the core urban area. Today being under cultivated arable land, site offers possibility to explore all segments of military and civilian urban life with wide use of multidisciplinary methods.
Historical sources say that Viminacium was a significant military stronghold where the Roman legion Legio VII Claudia Pia Fidelis was stationed. An important military center and a Roman provincial capital, Viminacium, was built on a territory belonging to the Celtic tribe Scordisci. It owed its size and significance to the rich hinterland in the Mlava River Valley, as well as to its exceptionally favorable geographical position, both within the defense system of the Empire's northern borders and as a crossroad for road, river and trade networks.
Site was continuously occupied from 1st – 6th century. Several times was destroyed in barbarian invasions (the Goths, the Huns and the Slavs) and rebuilt afterwards. The Hun invasion in 441/443 AD pushed city in full decline and after arrival of the Slavs at the beginning of 7th century site was completely abandoned.
In the late 19th and early 20th century, M. Valtrović and M. Vasić conducted excavations on the right banks of the Mlava River, at the Čair site, revealing the fortress rectangular base, 442 x 385 meters, as well as a large civilian settlement not far from its western rampart. Rescue excavations of several vast cemeteries of Roman Viminacium, mostly in second half of 20th century, yielded over 14000 graves and 30000 small finds. In excavations in the last two decades parts of legionary fortress and civilian settlement (amphitheater, thermae, etc.) were also explored, as well as number of villas, suburban settlements and workshops.
- Ram, Roman road below Ram Fortress, Veliko Gradište Municipality
On the step bank of the Danube, below Turkish mediaeval fortress, there is a section of the Roman road cut into the stone cliff. This part of the road was built by legionaries of the legio VII Claudia in 100/101 AD during preparations for the Trajan`s First Dacian war. Below mediaeval tower 5 there is an inscription carved into the flatten rock surface dedicated to god Jupiter celebrating this undertaking and mentioning vexillation of the VII Claudia legion under the command of centurion Gaius Licinus Rufinus. It the cliff there are still traces of pulling boats with ropes upstream. Road was used actively in centuries to come and abandoned only in modern age. This is among the last sections of the road still preserved, visible and presentable.
- Ram (Lederata), auxiliary fort, Veliko Gradište Municipality
The largest and the most important fort in the wider Ram area is located on a dominant plateau “Grad”, 1 km away to the east from today’s settlement, and was shielded with a stone cliff from the north, and two gorges cutting from the west and east.
The original fort was built during the 1st century AD in the period of the Roman occupation of the Danube area. It was particularly significant at the beginning of the 2nd century and Trajan’s First Dacian war. It is considered that at this place the main force of the Roman army crossed the Danube on a pontoon bridge made of small boats into the Dacian territory. This scene is depicted at the beginning of reliefs on the Trajan’s column in Rome. The crossing safety was additionally enforced by building a fortification on river island Sapaja and on the opposite Banat riverbank. This crossing remained in use throughout centuries. There is still a barge crossing today.
The first fort at Lederata was built in the late 1st century and was one of the largest auxiliary forts on Upper Moesian limes, measuring 200 x 150 m. It had a rectangular plan with rounded corners and with inner towers on corners and along the rampart. During late antiquity the reduction of defensive system occurred, and small fortlet was built in the north east corner of the older fortification. The fort was destroyed in 5th century and was rebuilt during the reign of Emperor Justinian. New massive ramparts were erected on the grounds of the larger, Trajan fort, with added exterior circular and semicircular towers, and additional protection (ditch, double embankment and another rampart). This fort is identified as Lederata.
Today visible stone foundation remains of the up to 3 m thick rampart and a rectangular fort of 140 m х 200 m dimensions, with 11 semi-circular towers and a main entrance on its south side.
- Golubac (Cuppae), auxiliary fort, Golubac Municipality
On a natural hill, rising over the Danube bank, with the Golubac settlement in between, there are massive remains of the Roman fortification walls. Towers and ramparts made of ashlars are visible on the surface and slopes of the hill as well as some buildings inside. Numerous finds testify to a settlement and a cemetery. Surface finds confirm presence of multiple auxiliary units and vexillations of IIII Flavia and VII Claudia legions. No archaeological excavations have been conducted. Limes Geophysical Survey project is in progress on the site.
- Golubac, Roman road below Golubac fortress, Golubac Municipality
The mediaeval fortress of Golubac rises over a part of a Roman road which is in this section cut into a rock. The remains of the road could also be seen at the foot of the fortress. Some 200 m to the southeast from the fortress there are remains of a buildings with massive walls. These are all part of Golubački grad Archaeological park.
- Čezava (Novae), auxiliary fort, Golubac Municipality
In the “Gradac” area where a torrential river Čezava flows into the Danube, by its left bank, there are the remains of a Roman fort which was a part of a Roman fortified military border on the Danube. With some dilemmas it is most commonly identified as the fort Novae, that is mentioned in historical sources. Archaeological research was conducted between 1965 and 1970, but the entire site hasn’t been explored. The research results show that life on sites can be divided into seven periods. All of them lasted in the time span from the first half of 1st century AD, when the first wooden fort was built, and until the 4th century. Massive rebuilding and strengthening were done during last phase in the period of Emperor Justinian (527–565). The fort suffered numerous modifications during the cited period, but its base kept its square form of 140 х 120 m dimensions, with rounded corners and 14 towers which were altering their appearance and only to some extent changed their position.
Due to the Đerdap I hydroelectric power plant construction the level of the Danube increased. Today interior of the fort is mostly submerged, as well as the north and parts of the east and west defensive walls. Vicus was located to the south of the fort in its immediate vicinity.
- Saldum (Cantabaza), auxiliary fort, Golubac Municipality
The Saldum site in the village of Dobra at the mouth of the Kožica brook was covered with waters of the accumulation lake after the construction of the Đerdap I Hydroelectric Power Plant. It was systematically investigated for four years in 1969–1970. The objective of the archaeological investigations at Saldum was the exploration of the area enclosed within the ramparts of the Early Byzantine fortification so the data concerning the complete area of this site in all its phases remained unknown to the investigators. It was possible to distinguish five horizons of life at Saldum, from the 1st to the end of the 6th century.
- Bosman (Ad Scrofulas), auxiliary fort, Golubac Municipality
Bosman fort remains are located at the beginning of the “Upper Gorge” about 1.5 km away from Gospođin Vir rock. Before the performed archaeological excavations, it was assumed that this had been a Roman stop Ad Scrofulas, but the 1968-1969 research show that the fort was built in an early Byzantine period, in the period of Justinian’s great restorations (527–565).3c
Narrow space of the plateau obliged builders to improvise only available solution to planning of defense. It had a nonstandard triangular ground plan with circular towers on the corners and a gate in the east rampart. The northeast tower, closest to the Danube was washed away. The triangular plan was imposed on the architects by the natural conditions, so they obeyed them to the fullest during the building period. The fort was destroyed at the very end of the 6th century and has not been restored again.
The entire site is submerged due to the Đerdap PP construction and a heightened water level.
- Gospođin Vir, Roman road and imperial inscriptions, Golubac Municipality
On the Gospođin Vir site there are the remains of a Roman road and a watch tower, and in the vicinity, in the area of Manastir there is a medieval church with a cemetery and a settlement; there is also a site with a prehistoric settlement. Together they make a wider unit which shows a long-life activity span on this very cramped space between the Danube the rocky riverbank.
The evidence of the Roman road construction through the gorge are the five monumental tablets of emperors Tiberius, Claudius and Domitian carved in the rocks. Road was partially cut into the rock by Legio IIII Scythica and Legio V Macedonica (under Tiberius) and then extended above water on wooden consoles making this technique unique on the frontier built in harsh conditions. Road was later widened and repaired by Legio IIII Flavia and Legio VII Claudia under Domitian. By the road there used to be a sentry box attached to the rock, so that it had only three stone walls and two small rooms inside. Base dimensions were 10.9 х 4.5 х 4.95m. It was built by the end of the 1st and the beginning of the 2nd century and was used in the 4th century too. The basic function of this watch tower was to control the road and observe the opposite bank.
The entire site was submerged due to the Hydroelectric power plant Đerdap I.
- Boljetin – Gradac na Lepeni (Smorna), auxiliary fort, Majdanpek Municipality
The occupation of the Smorna fort started in the 1st century and was completed in the 6th century. The investigations of the site established all the construction stages, from an earthen fort dating from the period when the road was built, period of Emperor Tiberius, to its restoration in the period of emperor Justinian. A well-documented stratification of the fort facilitates research of the Limes continuity in this section of the Danube River. This is one of the best preserved and best explored forts in salvage campaign of Đerdap I salvage project. The entire site was submerged due to the construction of hydroelectric power plant Đerdap I and a heightened water level.
- Ravna (Campsa), auxiliary fort, Majdanpek Municipality
The Campsa fortification was investigated in the 1967–1970 period. It was built at the turn of the 3rd century. All the fortification elements were found (the ramparts, the tower, the gates) and a great part of its interior. The fortress dimensions are 40 m x 40 m. In the 4th century, at their corners, the ramparts were reinforced with strong towers of various shapes and orientations. After a thorough restoration in the emperor Justinian period, the fortification was destroyed in the late 6th century. The entire site is submerged due to the Hydroelectric power plant Đerdap I construction and a heightened water level.
- Miroč (Gerulata), auxiliary fort, Majdanpek Municipality
The Gerulata fort is located high above the Danube, on a vantage spot from which it was possible to control all the movements along the main limes road. The remains of the massive ramparts are hidden in the shrubbery. The terrain configuration indicates that it may have been a structure of about 144 x 120 m dimensions. Archaeological and geophysical surveys showed solid preservation of buildings within the fort, and parts of ramparts still visible on the surface. Fortification was dated from 1st – 6th century AD. It was one of two stations protecting the limes road – main shortcut between Taliata (Donji Milanovac) and Egeta (Brza Palanka). Limes Geophysical Survey project is in progress on the site.
- Hajdučka vodenica, auxiliary fort, Kladovo Municipality
A Roman military outpost was built in the center of a fan-shaped plateau on the high bank, opposite the mouth of the Mraconia river (Romania). At this site, on the right Serbian bank of the Danube, well- preserved early Byzantine fort structures were discovered. Their dimensions are 70 x 50 m, with solid, strong ramparts, about 3.2 m thick, extremely well preserved from 4 to 7 meters in height, with round towers on corners and one polygonal tower. The remains of a late Antiquity square tower (burgus) were found in the center of the fortress. The size of the early Byzantine fortress was doubled by adding a fortified annex towards the edge of the plateau.
Part of the fort was submerged after the Hydroelectric power plant Đerdap I construction. Significant portion of the site is still visible on the shore of the accumulation lake.
- Trajan’s tablet / Trajanova tabla (Tabula Traiana), Roman road and imperial inscription, Kladovo Municipality
Roads are the most common Roman infrastructure, characteristic to all parts of the Empire. But those within the Iron Gates Gorge differ significantly. Because of the narrow gorge and steep cliffs there was no space to build a regular road. The legionnaires had to cut the road into the rock itself and to widen it by constructing a walking path supported by wooden consoles hanging above the river. This undertaking lasted for several decades, starting from 33–34 AD under Emperor Tiberius, with massive works and reconstruction under Domitian and finally completed under Emperor Trajan in preparations for the Dacian Wars. The Limes road was essential for communication, supply and transport between fortifications and settlements along the frontier. Road was also used to drag boats with ropes upstream against the Danube’s strong current. Rope cuts in the stone are still visible in some sections. This road remained in use by local population and border patrols until the 1970 when it was submerged. The endeavors of Roman army were recorded on an inscription above the road, so called Tabula Traiana, or Trajan’s tablet. This is an imperial inscription found in situ, on vertical cliff above the Roman road carved into a rock.
Trajan’s Tablet – Latin inscription:
IMP CAESAR DIVI NERVAE F
NERVA TRAIANVS AUG GERM
PONTIF MAXIMVS TRIB POT IIII
PATER PATRIAE COS III
MONTIBVS EXCISI. ANCO..BVS
Translation: Emperor Nerva, son of the divine Nerva, Nerva Trajan the Augustus, Germanicus, Pontifex Maximus, with the power of Tribune for the fourth time, Father of the Fatherland, Consul for the third time, cut the mountains and on wooden consoles built this road.
- Karataš (Diana / Zanes), auxiliary fort, Kladovo Municipality
The Diana Fort, also known as the Diana Cataracts Station (Statio Cataractarum Dianae) was built in Tiberius – Claudius age and rebuilt in the Flavian period of the 1st century AD. The main phase belongs to the fortification of Emperor Trajan. This fort protected the entrance to the canal that was dug in order to avoid cataracts in the main river course. These cataracts obstructed navigation along the Danube. In preparation for the Dacian Wars, Emperor Trajan dug this canal more than 3 km long and 40 m wide. This achievement was celebrated on the Imperial Tablet found near the fort itself.
The Diana Fort, as well as Pontes, is one of the archetypal Roman forts. With an area of over 3 hectares, it was certainly one of the largest auxiliary forts on the Roman borders.
The Diana Fortress is one of the best explored fortresses on the Roman frontier in the Upper Moesia. Together with Pontes, it has the status of a monument of an outstanding value in the Republic of Serbia because of its historical importance and preservation. The wider area of the fortress has been included in the preservation process.
According to the archaeological data, the military garrison of Dianae changed several times. Multiple units were documented both infantry and cavalry: detachments of Roman Moesian legions – V Macedonica, VII Claudia, IIII Flavia, XIII Gemina, as well as the auxiliary troops - Cohors VI Thracum and Cohors V Gallorum that has been confirmed in inscriptions.
Below the fort on the bank of Danube small port protected by defensive walls was partially documented.
- Kostol (Pontes), Trajan’s bridge and auxiliary fort, Kladovo Municipality
The Trajan’s bridge is often mentioned as the longest bridge in antiquity. It was depicted on Trajan’s column in Rome and on series of coins celebrating this marvelous achievement. Twenty stone and brick pillars held wooden construction that spanned over 1125 / 1200 meters across Danube. Human ingenuity of architect Apolodorus of Damascus, Trajan’s chief architect was here at its best. Bridge was built by the Roman legions, mainly of VII Claudia whose vexillations (detachments were stationed in Pontes and nearby Mala Vrbica – Konopište forts). Large canals, visible in the marshy terrain even today, were dug around in order to lower Danube level and make easier constructions of the pillars. Hence, the name Pontes – Bridges (pl.) as several temporary bridges had to be built across these canals and the Danube. Bridge was disabled after short time because of the danger of barbarian intrusions. Wooden construction was dismantled in the time of Hadrian, and later constructed and deconstructed several times as military and political situation changed. The last use of bridge was noted during rule of Constantine the Great. Today only several first and last pillars on Serbian and Romanian banks are visible, although existence of all other in the riverbed was confirmed by underwater research.
Castellum Pontes located immediately next to the Trajan's bridge (Pons Traiani), protected access to this wonderful river crossing. It lies on a high bank of the Danube, opposite the Romanian Drobeta / Turnu Severin fort. It was also known in late antiquity under the name Transdrobeta.
Although it was reconstructed over the centuries, it retained its original shape, characteristic of the auxiliary Roman fortifications of the Trajan's period. They were square fortresses with rounded corners and square towers on the inside of the stone walls, on corners and at the gates. The North Gate – porta praetoria and the South Gate – porta decumana, were placed in a central position of the rampart. The interior was also divided by an axis, according to the rules of the time, with the headquarters building – principium, in the center of the intersection of the two main streets. The north and east ramparts were discovered and conserved completely over the course of the previous works, as well as most parts of the west and south ramparts, all four gates, towers (16 out of 18?), parts of the headquarters building / principia, workshops, warehouses, and late Roman structures. After being considerably damaged during the 2nd century, all parts of the fortress were reconstructed during the Severus dynasty at the beginning of the 3rd century, as well as in the later periods. The fortress, like the Roman Empire and its frontiers in general, suffered great destructions in conflicts with the Goths and the Huns in the 4th and the 5th centuries AD.
- Mala Vrbica, Konopište, military post and supply center, Kladovo Municipality
Military post at Mala Vrbica was located in the vicinity of Trajan’s bridge and Pontes fort – some 3 km downstream. Complex was the garrison of troops that participated in building Trajan’s bridge. This military complex was at east side of the canal that was used to lower Danube water level while building the bridge. Earliest finds from site belong to the end of 1st and beginning of 2nd century AD. This post that spread further downstream along the river had the supporting role in building and potentially was main supply center garrisoned by soldiers from Legio VII Claudia. Some of the buildings were interpreted as barracks while massive granaries, storehouses and small port were documented also. Port being on the lower bank downstream was partially destroyed in previous centuries and then submerged into Danube being only basically documented prior to building of hydroelectric power plant Djerdap II.
- Rtkovo, Glamija, fortlet, Kladovo Municipality
This auxiliary fort consists of an earlier small fortification – tower based on the tetra pylon within a small defensive wall, and later larger rectangular fortification with round corner towers. This is the same type of fortlets as in Ljubičevac, Milutinovac, Hajdučka vodenica, Donje Butorke.
- Brza Palanka (Egeta), three auxiliary forts, Kladovo Municipality
The Egeta belongs to some of the most important sites along the frontier. There were three fortifications (Egeta I, Egeta II and Egeta III) of different shapes and from different periods dating from 1st to the 6th century AD. During the 2nd century it was a base of the Cohors I Cretum. In Late Antiquity it was confirmed as a base for the Danube fleet, but also there was a garrison of Legio XIII Gemina and cuneus equitum sagittariorum. In the vicinity large civilian settlement was documented but flooded by the Danube constantly from the 19th century. Multiple forts suggest radical changes in the organization of both the military and the civilian in a wider zone of Brza Palanka.
This was one of the few naval bases that have been confirmed along our section of the frontier. It had its own defensive system connected to one of the forts.
One of the best-known sanctuaries dedicated to Jupiter Dolichenus was excavated in the vicinity of Egeta I fortification.
- Mihajlovac - Mora Vagei, fortlet, Negotin Municipality
Fortlet is located on the bank of the Kamenički potok (Kamenica stream) near a water mill from a later period. Very good state of preservation. It consists of a watchtower and a defensive wall surrounding it (burgus type). The fortification existed from the 1st – 6th centuries AD with at least three construction and destruction phases. Excavations collected a lot of data on the organization and architecture of this small frontier post.
- Prahovo (Aquae), Late Roman city, Negotin Municipality
One of the most important sites downstream from the Iron Gate. The site was confirmed as a river port. During late antiquity it developed into the one of the largest urban centers of province Dacia Ripensis. City was also one of the earliest Episcopal sees in late Roman Illyricum. Archaeological site remains under modern Prahovo and only one segment of massive city defensive walls is visible today.
- Radujevac, Ćetaće, fortlet, Negotin Municipality
A small rectangular fortification that protected the road and access to a bridge over the Timok river. F. Kanitz left a drawing of the fortification in the late 19th century. Small scale archaeological excavations dated the site into late antiquity after the abandonment of the province Dacia. Pottery and rubble belonging to vicus spread over vast area towards north west of the fortlet. Limes Geophysical Survey project is in progress on the site.
Justification of Outstanding Universal Value
The Serbian section of the Danube Limes7 is part of the future transnational property “Frontiers of the Roman Empire – The Danube Limes” which ultimately should be united as part of the entire property of the Frontiers of the Roman Empire. Complexity of military infrastructure and solutions applied in the defense of the Empire together with civilian components that differentiates the frontier as a unique and special zone of extended development and cultural impact that lasts for centuries adapting to harsh and rapid geopolitical changes creates a remarkable value and addition to outstanding universal value of the Frontiers of the Roman Empire as a whole.
The proposed Site would encompass the known, still existing and scheduled fortifications and other frontier elements between Neštin and Rakovica along the Danube, as mentioned, and all the additional features will be included according to the Koblenz Declaration of the Bratislava Group including the civil towns and settlements and cemeteries adjacent to the military fortifications (list of sites enclosed in the Annex). The river itself and the temporary fortifications beyond the borderline will not be part of this World Heritage proposal.
Criterion (ii): The frontiers as a whole reflect the development of the Roman military architecture and the impact of the frontier on the growth of transport routes and urbanization.
The extant remains of the Frontiers of the Roman Empire – The Danube Limes constitute significant elements of the Roman Frontiers 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 the new concept of 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 had the possibility to adapt to situation from war zone to be the bridge for trade, imposing cultural or political influence. It 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 Roman frontier is the largest monument of the Roman Empire, one of the world’s greatest preindustrial empires. The physical remains of the Limes, forts, watchtowers, settlements and the hinterland dependent upon the frontier reflect the complexities of the Roman culture but also its unifying factors across Europe and the Mediterranean world.
Unlike the Roman monuments already inscribed, the FRE’s constructions are evidence from the edges of the Empire and reflect the adoption of and resistance to the Roman culture by its subject peoples. The frontier was not an impregnable barrier: rather it controlled and allowed the movement of peoples within the military units, amongst civilians and merchants, thus allowing the Roman culture to be transmitted around the region and for it to absorb influences from outside of its borders.
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 Frontier reflects the power and might of the Roman Empire and the spread of classical culture and Romanization which shaped much of the subsequent development of Europe, the Near and Middle East and North Africa.
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.
7 The original Tentative list of the Republic of Serbia submitted in 2015 was intended as an extension to the existing World Heritage property the “Frontiers of the Roman Empire” (ref. no. 430ter), which at present consists of the Hadrian's Wall, the Antonine Wall (UK) and the Upper German Raetian Limes (Germany). After numerous meetings, consultations with ICOMOS, and WHC session in Krakow in 2017 the new transnational concept of nomination was adopted and Serbian part of the Frontiers of the Roman empire is part of the new property Frontiers of the Roman empire – The Danube Limes.
Statements of authenticity and/or integrity
The Limes Road was documented in several zones. It was best documented during the rescue excavations in the Iron Gate gorge. The second zone of the frontier road was documented in the area east of Viminacium. A part of the fortifications lay under modern settlements (Singidunum, Cuppae). The value of the Serbian frontier section is that the majority of the fortifications are in the open areas without modern settlements above (Margum, Viminacium, Lederata, Hajdučka Vodenica, Boljetin, Diana, Pontes, Egeta).
Over the last 2000 years the river has often changed its course over longer distances. Because of these changes and floods some sites on the lower grounds were partly or completely destroyed by water. In the 19th century the Danube River underwent extensive management measures, which did not help to preserve the monuments. But quite a lot of them were detected and investigated as part of those activities. Another threat is the waterpower stations with their dams and reservoirs. When power stations were built in Serbia during the 1970s and 1980s, a long stretch of the Roman frontier, e.g. forts, fortlets, watchtowers and the road through the Iron Gate were submerged and are not visible any longer.
Fieldworks carried out for more than 100 years, and even more research activities and rescue excavations, especially during the last 40 years, have disturbed and even partly destroyed the Roman remains in nearly all of the proposed World Heritage sites. Many excavations have demonstrated that the remains of the Limes monuments have survived remarkably well. There are still many invisible, undisturbed and uncovered elements of the property in most of the Limes sites. The visible parts are kept in good condition, cared for by the local or regional authorities and are scheduled under the Federal Monument Protection Act. Some of the very few reconstructions, mainly in Viminacium, will be included in the buffer zone.
The inscribed component parts have a high level of authenticity and those nominated in the future will also all be selected for their high authenticity. Each of the component parts inscribed to date has been extensively studied and researched and its authenticity has been verified. This will continue to be the case for any new components. The materials and substances of underground archaeological remains are well-preserved as are the upstanding and visible ones.
Justification of the selection of the component part(s) in relation to the future nomination as a whole
The Limes or Frontier of the Roman Empire is a full and continuous line of defense. It is complex of large, auxiliary and small fortifications with adjacent civilian settlements, production centers etc.
The linear defense system was established and rebuilt in several stages. Its establishment began in the first quarter of the 1st century AD from the west, and went on downstream the Danube through the 1st and the beginning of the 2nd century AD. After abandonment of Dacia in 271 frontier that was built in the early 2nd century again came to focus and was reestablished on the Danube. Emperors of the tetrarchy and Constantine made extraordinary efforts to strengthen defense and that is clearly visible in archeological finds.
With the line of 450 km Serbia holds significant segment of the frontier. The key events for the empire took part here including preparations and waging for wars with Dacia, numerous wars with barbarians in Pannonian plains with Germanic or Sarmatian tribes (2nd-4th century). The Hun invasions in the first half of the 5th century, and the ultimate invasion of Avars and Slavs in the late-6th and early-7th century brough the end to this defensive concept. Limes was also a crucial zone during several civil wars of the 3rd and 4th centuries that significantly destabilized and weakened Empires defense.
Limes was a kind of buffer zone not just in defense of the Empire but also and in influence on tribes on the opposite bank, in trade, political and cultural influences. Frontier become a connection for intense cultural exchange between not only Rome and Barbaricum, but also between East and West as the troops constantly moved in order to intervene at weak points. Military formations spread customs and religious beliefs across the Empire. Throughout this time Roman Empire showed extraordinary ability to build and adapt its frontiers to protect or attack, trade and influence within and abroad making limes the most developed area of the provinces. With the permanent concentration of troops and with the largest density of civilian population frontier become the best developed region from administrative, economic, and military point of view. Large cities and often the provincial capitals were established alongside largest fortifications in this zone also.
Distinctive geographical and natural conditions of the Danube banks in Serbia influenced the positioning of the Roman military sites and infrastructure. Roads, bridges, canals and ports celebrated on monumental military and imperial inscriptions and columns (Columna Traiana in Rome, Tabula Traiana etc...) in the Iron Gate comprise a complex and unique system of defense system and communications observed nowhere else in the entire Roman Empire.
Comparison with other similar properties
The Serbian section of the Roman frontier is part of the river frontier along the Danube which stretches from Bavaria to Romania and the Black Sea, protecting the Roman Empire from the tribes from the North. Eight countries: Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria and Romania, share this system. Although the proper Latin name of this type of frontier is rippa, a better known and more commonly used word limes is the one for the nomination of this section in Serbia.
Beside the Danube, there are more river frontiers such as the Rhine river frontier in Western Europe and the Euphrates frontier in the Near East. There are major structural differences in river frontiers compared to the land ones. A 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 (watchtowers, fortlets, forts). This can be demonstrated through and seen in the already existing parts of the World Heritage property: Hadrian’s Wall, the Antonine Wall or the Upper German Raetian Limes. The relationship between the individual frontier elements is clearly visible.
All 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 present. The forts along the Rhine and the Danube river frontiers are between 10 km to 30 km apart, and inter-visibility often does not exist.
Limes road was often lifeline of the frontier and parts of the road along Danube in the Iron Gates prove importance and ingenuity of Roman military engineering. Road cut into the stone cliffs and then extended on wooden consoles above water is a unique solution found only at Serbian section of the frontier. This marvelous engineering undertaking was celebrated on several imperial tablets curved into the stone walls of the gorge. Other architectural achievements include Trajan’s canal between Sip and Karataš, going around the Danube cataracts (destroyed in previous centuries) and Trajan’s bridge over Danube between Pontes and Drobeta.
When chronology is in question, frontier in Serbia lasts much longer than sections in the west. Although it still cannot be treated as permanent frontier but line of defense against barbarians and springboard to conquest of Dacia military presence can be documented from the first decades of 1st century on many of the sites. On the other hand, when the western part of the Empire collapsed in 476 AD limes in the East continued to stand and was restored multiple times after catastrophic invasions. The Avar and Slavic invasion in 602 AD can be identified as ultimate end after which it was clear that frontier was annihilated, never restored and Danube region lost to the Roman Empire.
A distinctive feature of the rivers Rhine and Danube frontiers are chains of watchtowers along one side of the river course and bridgehead fortifications. Watchtowers, the intermediate elements in the archaeological landscape, are not so easy to detect along the river frontiers. Those of the earlier Roman Empire were mainly made of timber. The Late Roman watchtowers are easier to discern because of their massive stone construction. More than 200 watchtowers, mostly stone ones, are recorded along the Danube banks, most of them in Hungary, forming a very tight defense system. It can be assumed that similar systems existed on the other Danube frontier sections too.
There are several points where bridgeheads are clearly established in order to trade or secure the river crossings. In the times of war these were used to secure a beachhead for an invasion to an enemy territory. In times of peace they were used to provide landing infrastructure at crossings or to secure both sides of bridges. These natural pairs of fortifications were often named in pairs like Margum and Contramargum, Dierna and Transdierna, Drobeta and Transdrobeta (Pontes). Some of these bridgeheads were located in Dacia (present day Romania).
Although there are no clearly identified bridgehead fortifications in Austria, there are such sites known for example in Iža in Slovakia. Most of them were constructed when Roman politics caused advances of the army into a Barbarian territory. In the late antiquity 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 some 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 disintegration of 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 period.