Sangarius Bridge

Sangarius Bridge
View of the remains of the triumphal arch on the western end of the bridge (1838)
Carries	Road from Constantinople to east in Byzantine times
Crosses	Çark Deresi (Antiquity: Sangarius)
Locale	Close to Adapazarı, Turkey
Characteristics
Design	Arch bridge
Material	Limestone blocks
Total length	429 m
Width	9.85 m
Height	10 m
Longest span	24.5 m
No. of spans	7 main arches + 5 floodways
Piers in water	6
History
Construction end	562 AD
Cutwaters on both sides Sangarius Bridge

The Sangarius Bridge or Bridge of Justinian (Turkish: Justinianos Köprüsü or Beşköprü) is a late Roman bridge over the river Sakarya (Latin: Sangarius) in Anatolia, in modern-day Turkey. It was built by the East Roman Emperor Justinian I (527-565 AD) to improve communications between the capital Constantinople and the eastern provinces of his empire. With a remarkable length of 430 m, the bridge was mentioned by several contemporary writers, and has been associated with a supposed project, first proposed by Pliny the Younger to Emperor Trajan, to construct a navigable canal that would bypass the Bosporus.

The Sangarius Bridge is located in northwestern Anatolia, in the ancient region of Bithynia, ca. 5 km southwest of the town of Adapazarı. Today, the bridge spans the small Çark Deresi stream (called Melas in Antiquity), which flows from the nearby Sapanca Lake; the modern course of the far wider Sakarya lies 3 km to the East.

In Antiquity and the Middle Ages, the bridge served an important purpose: it was the crossing-point of the strategically important military road from the Bosporus to the eastern provinces of the Roman Empire, which were threatened by the Sassanid Empire. Before the stone bridge was constructed, a wooden pontoon bridge existed, which, according to Procopius, was frequently washed away when the river flooded, costing many men their lives.