abstract:The Valens Aqueduct (, meaning "Aqueduct of the grey falcon"; , Agōgós tou hýdatos, meaning simply "aqueduct") is a Roman aqueduct which was the major water-providing system of the Eastern Roman capital of Constantinople (modern Istanbul, Turkey). Completed by Roman Emperor Valens in the late 4th century AD, it was restored by several Ottoman Sultans, and is one of the most important landmarks of the city.