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For the last meeting in Border Archaeological Society's spring series, Jim Crow, Professor of Classical Archaeology at the University of Edinburgh, gave a talk entitled The Longest Roman Water Supply Line: Exploring The Water Supply Of Byzantine Constantinople.

Saturday, 23rd June 2018, 9:00 am

It is only in the past 25 years that archaeologists and engineers have been able to document and study one of the most extensive hydraulic supply systems of the ancient world: the system of aqueducts and cisterns of Constantinople, now Istanbul.

The system was very complicated and sophisticated. Many aqueducts built in the later Roman Empire even surpassed the one we know today as the Pont du Gard.

Within the historic city are the remains of more than 200 cisterns and a huge bridge, the Valens Aqueduct (known in Turkish as the Bozdogan Kemer). This remarkable stone bridge was built in 373AD by the Emperor Valens, 364-378AD, and transported water to the city up until the 20th century. Today, traffic snakes through its bottom arches, and the bridge is covered with early Christian symbols.

It was Hadrian, 117-138AD, who started building water systems, and as the city grew, Constantine, 306-337AD, who converted the Roman Empire to Christianity, continued the work.

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The fall of the ‘Iron Curtain’ in 1989-91 ushered in a new area for research. Before that, the region of Thrace, the part of Europe West of the Bosporus, was too close to the Bulgarian and Romanian borders and closed to investigation. It was here that the Anastasian Wall was constructed in the late fifth century to protect the city and an extensive, long-distance water system was built.

The area is very hilly, in places up to 1,000m, and covered in trees. Especially in summer, remains and ruins are hard to see. But scientists were able to explore and map the system. Using GPS, they discovered remains not easily seen and found deep channels, bridges over valleys and systems of cisterns.

The first long distance channel was 246km and built in the fourth century, and the second was 180km. Bridges were built across valleys to avoid long channels as the water snaked towards the city.

The magnificent aqueduct at Kursunlugerme, 30m high and some 140m long, is situated some 60km from Constantinople and very well preserved. It is also covered in Christian symbols, proving that Christianity had triumphed. The Buyulkgerme aqueduct was 135m long, and the Kumarlidere 130m, illustrating the immensity of the work. Estimations of the quantities of mortar required for channels, etc, would fill 305 Olympic swimming pools.

Some bridges were rebuilt in the eighth century – an attempt to restore the city, which had been in crisis, and work continued for another 300 years, up until the 11th and 12th centuries.

In the city itself, Byzantium, at the Eastern end, was low-lying, whereas Constantinople occupied higher ground. Storage was needed as there were no rivers. Water was used for such institutions as baths, elite houses and monastries, with the elite being allowed pipes up to 3ins.

There were 211 cisterns in the city of varying sizes, many underground. The cistern of Aetius, 421AD, is now a football stadium, another is a playground. Binbirkirek, also known as the cistern of Philoxenos, from circa 500AD, has 1,001 columns and has been made into a tourist attraction. The largest and most magnificent is the Basilica Cistern, near the Hagia Sofia, built by Constantine and later enlarged – with its enormous vaults and arches it looks like some sort of place of worship.

We know Constantine imported grain from Egypt, and systems of storage and distribution were needed for this, as well as water. Stone water pipes suggested that the water was under pressure. Not much lead was used. When the metro was being built, ancient ceramic pipes along the colonnaded street were uncovered.

There are still lots of unanswered questions and we are still trying to piece it all together. We know that the later crusaders and Arabs (11th and 12th century) marvelled at the drains they saw in the city. The system went on until the 13th century – and then it failed.

The Border Archaeological Society’s series of lectures will resume in September.