William of Malmesbury
After the First Crusade's passage through Constantinople, both William of Malmesbury and Odo of Deuil mentioned the working Aqueduct of Valens in their histories. William of Malmesbury claimed that the Danube's water was carried into the city by hidden channels and washed the dirt from Constantinople, while Odo of Deuil stated that "from the outside conduits flow in, bringing the city an abundance of water". At this time, the city was the largest in Christian Europe, its population sustained by the water supply.