Guide
The Bridge of Justinian, also called the Sangarius Bridge and known locally as Beşköprü, is a late Roman stone bridge over the Sakarya river, five kilometres from Adapazarı in the historical region of Bithynia. It was built by the Eastern Roman emperor Justinian, who reigned from 527 to 565, to ease communication between the capital at Constantinople and the eastern provinces of the empire. At almost 430 metres long it was so large that writers and poets of the age took it as a subject. UNESCO added it to the Tentative List in 2018.
According to the late Roman historian Procopius it replaced a floating bridge of boats lashed together: the current was strong enough to break the boats loose and carry them away, and each time it did, passage over the Sakarya was cut. Justinian's decision to build in stone is also thought to have had to do with the strategic weight of the crossing, since the ancient royal road running from Constantinople to the frontier of the Sasanian empire — against which he fought often — passed this way.
The dates of its building can be fixed closely from literary sources. Work began in the autumn of 559, when Justinian returned from a tour of inspection in Thrace, and was finished after the peace concluded with the Sasanians in 562. The historian Theophanes puts the start in the year 6052 of the world, which falls in 559 or 560, and the completion in 562 can be read from the poems of Paulus Silentiarius and Agathias in praise of the emperor and his works. The bridge in turn dates a book: because Procopius says in De Aedificiis, his important work on late Roman architecture, that the bridge was still being built, that work can be taken to have appeared in 560 or 561 — five or six years earlier than is generally supposed.
The river has since moved. The old bed of the wide Sakarya has shifted about three kilometres east, and the bridge now stands over the small Çark stream, known in antiquity as the Melas, an outflow of Lake Sapanca, the ancient Sophon.
The bridge is built entirely of limestone and is well preserved. With the abutments at each end it runs 429 metres long, 9.85 metres wide and about 10 metres high. Its grandeur lies in the arches, each between 23 and 24.5 metres wide, carried on piers about six metres thick. The five arches in the middle of the river end in two more, one of 19.5 and one of 20 metres; the Çark stream now runs under one of the arches on the western side. Outside the river bed, in the flood zone, are five further arched passages between three and nine metres wide to protect the bridge from floods — two on the west bank and three on the east, the eastern ones partly destroyed during the building of a single-track railway. The two piers where the bank gives onto the seven arches over the river bed are each about 9.5 metres thick. The end stones of the seven great arches probably once carried crosses; only two survive.
Every river pier is shaped as a cutwater, pointed upstream and rounded downstream, with one exception: the widest pier, nine metres across on the western bank, is pointed on both faces. In this the bridge stands apart from other known Roman bridges, most of which use pointed cutwaters in both directions.
Two structures stood at the ends. At the west end there was, until the nineteenth century, a triumphal arch of the kind common on Roman bridges, now gone. At the east end an apse still stands, of unknown function; this round structure facing east is thought to have been a religious altar, and is eleven metres high and nine wide. Both the arch and the apse were drawn in 1838 by Léon de Laborde, whose drawing shows a round-arched gate built entirely of cut stone opening directly onto the bridge; another sketch gives its dimensions as 10.37 metres high and 6.19 wide, with piers 4.35 metres thick, one of them holding a spiral stair. The bridge also carried an inscription with a Greek epigram by Agathias. The inscription has not survived, but its content is preserved in the writings of the emperor Constantine Porphyrogenitus.
Some specialists today read the bridge as evidence of a great canal project supposed to have been planned in Justinian's time and never carried out, whose purpose would have been to join the Sea of Marmara to the Black Sea by canals across Anatolia, bypassing the Bosphorus. The earliest records of such a plan are in the correspondence between the emperor Trajan and Pliny, governor of Bithynia, in which Pliny proposed digging a link from Lake Sapanca near the Sakarya to the Propontis; that project is thought never to have been carried out, not least because Pliny died soon afterwards. Moore holds that Justinian planned to turn the part of the Sakarya flowing to the Black Sea westward into Lake Sapanca and so to realise Pliny's project, and points to the enormous scale of the bridge compared with the width of the river running beneath it. The claim is debated among specialists.