The Bridge of Justinian, also known as the Sangarius Bridge, is a late Roman bridge with a remarkable length of 350 m, constructed to span the Sangarius River in the ancient region of Bithynia in northwestern Anatolia. The bridge is located in the Beskopru neighbourhood within the Serdivan district, ca 5 km southwest of the town of Adapazari in northwestern Turkey. Today, the bridge spans the smaller Cark Deresi stream (called the Melas stream in Antiquity), which drains the nearby Lake Sapanca, whereas the modern course of the Sangarius currently lies 3 km to the
East. It was built by the East Roman Emperor Justinian I (527-565 AD) to ameliorate the transportation and communication between the capital Constantinople and the eastern provinces.
Considered one of the most significant late Roman and Byzantine emperors, Justinian aimed to restore the former glory of the Roman Empire through ambitious military campaigns and an empire-wide construction drive producing new religious, administrative and military buildings and structures. Located at the crossing-point of an important military road, hence the Bridge of Justinian had a geostrategic significance linking the western provinces and the Bosphorus to the eastern territories of the Roman Empire. According to various ancient sources including the De Aedificiis of Procopius that records the building projects of Justinian, this stone masonry bridge was constructed to replace an inadequate timber pontoon bridge that was frequently swept awayi. Referring to the same sources, there is controversy in ancient references to the precise start date of its construction but the construction of the bridge is known to be completed in AD 562.
This masonry bridge is made of limestone blocks, and has a length of 365 m, including the abutments at each end, with a width of 9.85 m and a height of up to 10 m. The bridge rests on seven central arches that have a span of approximately 23 m, which are complemented by five smaller arches serving as spillways in case the river overflows on either side, adding up to twelve arches in total. Based on earlier descriptions, the key stones of the main arches were decorated with single crosses in relief that are no longer visibleii. The central arches are supported by six piers of 6.5 m height and 6 m width, that have substantial buttresses serving as breakwaters. These piers are in rounded shape on the upstream southern side and are pointed on the downstream northern side. This significant feature differentiates the Bridge of Justinian from the majority of Roman bridges, which have pointed cutwaters facing upstream. Only on the western end of the bridge there are two low-pointed breakwaters situated both on the northern and southern sides.
The bridge structure was supplemented by an additional masonry structure attached to the south face at the eastern side, which partially blocks the adjoining small arch. According to Whitby (1985), this structure was built in two or more phases shortly after the construction of the bridge to function as a large breakwateriii. It embodies a pair of vaults partially demolished, which is supported by five piers that are still standing. The masonry building technique employed in its construction and its workmanship is similar to that of the bridge and the piers are decorated with similar cornices as that of the buttresses.
As a representation of the majesty of the bridge, the nominated property also included a monumental triumphal arch that used to span the western entrance and the remains of a large apsed structure facing the bridge whose former function is unclear. In the illustrations of Léon de Laborde and the descriptions of Texier dating back to 1838, the triumphal arch is depicted as an arched entrance made of stone masonry that is approximately 10 m high and 6 m wide, supported with two pillars of 4.35 m thicknessiv. The apsed structure is considered to be constructed as a decorative parallel to the western triumphal arch but the situation of the apse towards east gives the impression that it might have been built as an open-air shrine. The 11 m high apse is covered by a barrel vault supported by two piers who are continued in the direction of the bridge. The bridge was also decorated with an inscription that has not survived today but which bears an epigram in Greek by Agathiasv.
In the Antiquities and Middle Ages, the bridge is known to have fulfilled its original purpose of linking the main Roman military highway to the east across the Sangarius. The river shifted to an easterly course later in the thirteenth century, probably into its modern channel, and its former channel traversed by the Bridge of Justinian was occupied by the minor Melas (Çark) river. Nevertheless, the bridge continued to function as an important passageway until the late 20th century, and contributed greatly to the formation of a urban settlement in vicinity, which was named as Beşköprü (Five Bridges) after the Greek name of the bridge, Pontogephyra.
The Bridge of Justinian is an outstanding example of the late Roman technical and architectural expertise, and demonstrates technical and cultural interchange through the elaboration of these skills, organisation and knowledge. It is also the only early Byzantine period arched bridge that has survived to date, thus has a significant role in the Byzantine architectural history.
The bridge was built under the Emperor Justinian I who was credited to be one of the greatest emperors in late Roman and Byzantine history. As a representation of his achievements in the fields of art, architecture, and military conquest, this bridge conveys symbolic value associated with Justinian’s ambition to connect the eastern and western territories and to revive the greatness of the Roman Empire, in addition to its historic, architectural and technical significance. The references to the bridge construction in ancient sources also enhance its exceptional importance.
Writing about Justinian’s extensive building schemes and achievements, Preoccupies also narrated about the construction of the bridge. Agathias, Paul the Silentiary, Theophanes and Porphyrogenitus are other ancient writers describing the grandiosity of the bridge built by Justinian over the mighty Sagariusvi.
The bridge structure embodies a high degree of expertise in the technical mastery of stone masonry constructions and Roman military architecture. The unique design of the pier buttresses distinctive from the rest of the Roman bridges is a historical testimony of the diverse responses of the Roman technical skills to local geography and natural landscape. The completion of the bridge design with additional structures and breakwaters shortly after its construction also demonstrates how the structural system was later elaborated and perfected by engineers.
The Bridge of Justinian has maintained its physical, visual and functional integrity to a great extent until recently despite the change of the main river flow in the thirteenth century, surviving as one of the most outstanding and intact Roman bridges worldwide.
Criterion (iii): The Bridge of Justinian bears an exceptional historic evidence of the ambitious and coherent system of transportation, communication and military constructions proliferated during the reign of Emperor Justinian I in association with his aspiration of restoring the greatness of the Roman Empire back to its former glory. Connecting the capital Constantinople and the reconquered Western territories to the Eastern provinces, the bridge is attributed exceptional symbolic significance that is physically manifested in the outstanding bridge design embodying a monumental triumphal arch and the apsed structure at the eastern end. This nominated property thus illustrates and reflects the complex architectural, technological and organisational abilities of the Roman Empire, which allowed them to expand and transmit the Roman building culture around the region.
Criterion (iv): The Bridge of Justinian is an outstanding example of the late Roman architectural-engineering cultural accumulation and its excellent use in military structures and public works. The original composite design of the pier buttresses combined with the rounded cut-waters demonstrates the variety and complexity of the Romans’ responses to specific geographical, topographical and climatic challenges, as well as to the political, military and social conditions. It thus constitutes an exceptional example of the sophisticated architectural and technical skills of Roman engineers developed over the course of several generations.
The nominated property including the Bridge of Justinian, its supplementary structures and the protected areas surrounding it that are designated as an archaeological site as a whole embody and convey all the Outstanding Universal Values attributed to the site in terms of its architectural, technical-technological and symbolic significance. The bridge structure has managed to survive to date without any substantial alterations and its physical fabric is generally in good condition.
The Bridge of Justinian is under the protection of the national conservation legislation, specifically the Turkish Regulation for the Preservation of Cultural and Natural Property, Law no: 2863. It was registered as an “immovable cultural property to be protected” by the decision of the Superior Council for Immovable Antiquities and Monuments dated 05.02.1982 and numbered 13517. The registration of the property including the bridge and its supplementary buildings was later revised in the national inventory as a “Grade I archaeological conservation site” in 1986 based on the Decision No. 1900 of the Superior Council for Cultural and Natural Properties, which is surrounded by a Grade III archaeological conservation site that serves as a buffer zone in regards to the decision of the Kocaeli Regional Council for Conservation of Cultural Properties dated 23.01.2013 and numbered 814. In this context, the Directorate General of Highways is directly responsible of maintenance, repair and preservation of the Bridge of Justinian; whereas the responsibility for the conservation and safeguarding of the conservation area registered as an Grade I archaeological site belongs to the local peripheral bodies of the Ministry of Culture and Tourism.
Although some minor parts have been partially altered and deteriorated as a result of natural decay processes and shifts in land use policies, the integrity of the nominated property is manifested in the physical and structural integrity of the bridge structure, the visible remains of the supplementary buildings and the buried archaeological features within the registered conservation area. A short section of the causeway located close to the eastern end was demolished to allow the passage of the branch railway line to Adapazarı in the late nineteenth century. The bridge was closed to motorway traffic in 1995 following a conservation practice carried out by the General Directorate of Highways on the bridge that resulted in the change of the passageway stones and addition of three steps to both ends in order to allow pedestrian passage. A recently approved conservation work will also be undertaken soon by the General Directorate of Highways to structurally consolidate the bridge structure in order to control the negative impact of natural deterioration processes and to conduct archaeological excavations in the protected area, which will abide by the national conservation regulations and universal conservation principles.Authenticity
The monumental Bridge of Justinian and its material substance are generally well-preserved, and it has sustained its historic, aesthetic, age and rarity, functional and technical values to date without any significant modifications in its original form and design, building system and materials, as well as its use and function.
The authenticity of the form and design of the bridge and its supplementary structures are clear and comprehensible. Conservation and consolidation measures that have been carried out in the interest of better understanding and protection of the historic structure aligns with the setting of the property and does not have a negative impact on its authenticity. Despite the shift in the flow of the Sagarius River, it has served for pedestrian, equestrian and vehicular traffic uninterruptedly until very recently. Although the monumental triumphal arch facing the bridge is no longer standing and the apsed building at the other end is partially demolished, the symbolic significance of the Bridge of Justinian is still sustained in the physical and visual integrity and authenticity of the structure, as well as the spirit of place valued by the users and visitors.
The Bridge of Justinian constitutes an exceptional historical testimony in terms of architectural- engineering specifications, original building design, workmanship, technical skills and their adaptation to the local geography in comparison to other Roman bridges and road structures, as well as those from latter periods that are both inscribed and not inscribed on the UNESCO World Heritage List and/or Tentative Lists.
While the majority of Roman arched bridges with pier buttresses have pointed cut-waters facing upstream river, adorned either with a pointed downstream tail or with no tail at all, the Bridge of Justinian has an original design distinguished with the shape of the pier buttresses. The most common design for pier cut-waters on Roman bridges is angular but the Bridge of Justinian is an exception with a composite pier design combining angular buttresses at one side and rounded at the opposite end of the same pier. It is also distinguished from other similar and contemporary structures with its remarkable dimension of 9,85 meter width.
As for the construction technique, masonry arched structures and bridges were largely used in the region over various periods due to its convenience in spanning large distances. Among those located in Anatolia/Asia Minor region, the Malabadi Bridge distinguished by its largest arch span and the Bridge of Uzunköprü as the longest stone bridge are some of the most known arched bridges in addition to the Bridge of Justinian, which are both inscribed on the World Heritage Tentative List of Turkey. However, both of these bridges were constructed in latter periods: the Malabadi Bridge represents the twelfth century Artuqid period and the Bridge of Uzunköprü was built in the fifteenth century. Hence, the Bridge of Justinian stands out one of the earliest arched bridge structures dating back to late Roman period that has survived to date intact. Comparatively, there is limited data on other masonry bridge structures dating from the Roman and Byzantine periods in Anatolia, such as the Aesepus Bridge, Macestus Bridge and the Constantin’s Bridge in the ancient region of Mysia, due to the fact that they have been largely demolished or collapsed over the years.
In this context, the Bridge of Justinian stands out as an outstanding example of the Roman cultural-technical accumulation contributing to the development of the Roman technical and engineering skills. It also constitutes a physical manifestation of the systematic and extensive building programme employed during the Roman Empire, resulting in dense networks of carefully engineered and well-maintained roads and bridges. While Roman military structures and bridges are generally well documented and preserved in Western and Eastern Europe, such as the Alcantara Bridge inscribed on the World Heritage List, the Bridge of Justinian is distinguished with its massive size, geopolitical significance and physical integrity in the Asia Minor/Anatolia region. Regarding its significant geostrategic position, it also symbolises the military and political achievements of Justinian in connecting the eastern and western territories of the Roman Empire and reviving its former glory to a great extent.