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The Aqueduct of Valens (Bozdoğan Kemeri) is one of the most important ancient structures in Istanbul, Turkey. It’s included in the UNESCO World Heritage listing of the Historic Areas of Istanbul.
History of the Aqueduct of Valens
The Aqueduct of Valens was built in the late 4th century to provide water to the city of Constantinople, which at that time was the capital of the Eastern Roman Empire. Construction started during the reign of Emperor Constantius II and was completed in 368 under Emperor Valens. It was connected to a water supply system that began under Emperor Hadrian in the early 2nd century.
After completion, the aqueduct reached over 268 kilometers (167 miles) in length. In the 5th century, an extension added 451 kilometers (280 miles) of conduits that took water from Vize, 120 kilometers (75 miles) away from Constantinople. It was the longest water system in antiquity.
Once the water reached Constantinople, it was stored in three open-air reservoirs and hundreds of underground cisterns, such as the Basilica Cistern. The aqueduct was extended, maintained, and used throughout the Byzantine and Ottoman Empires, and eventually supplied water to Topkapi Palace. In the 1950s, it had a daily discharge of 6,120 cubic meters (216,000 cubic feet).
Bridge of the Aqueduct
The bridge of the aqueduct spans Atatürk Boulevard and is best seen from the Saraçhane area. According to tradition, it was built using stones from the walls of Chalcedon (today’s Kadıköy), which were pulled down in 366 as punishment for the revolt of Procopius.
The aqueduct runs for 921 meters (3,020 feet) and has a total of 73 arches. In 1912, a 50 meter (160 foot) section near the Fatih Mosque was torn down.
Arches 1-40 and 46-51 date back to the time of Valens. Sultan Mustafa II built arches 41-45, and Süleyman the Magnificent built arches 52-56. Arches 18-73 are double arches while the rest are single arches.
The width of the bridge is between 7.75 meters and 8.24 meters. The pillars are 3.7 meters thick, and the lower arches are four meters wide.
