Metropolis of Pergamon
The Metropolis of Pergamon () was an ecclesiastical territory (diocese) of the Ecumenical Patriarchate of Constantinople in western Asia Minor, modern Turkey. Christianity in the city of Pergamon (modern Bergama), was introduced already from 1st century AD, while the local Christian community comprised one of the seven Churches of Asia mentioned at the Book of Revelation, written by John of Patmos. The bishopric of Pergamon was twice promoted to a metropolis: during the 13th–14th centuries, as well as for a short period in 1922. Today the "Metropolis of Pergamon and Adramyttium" is the see of a titular metropolitan.
Pergamon
The Madradağ aqueduct was a ceramic pipe with a diameter of 18 cm which already brought water to the citadel from a source over 40 kilometres away in the Madradağ mountains at 1174 m above sea level in the Hellenistic period. Their significance for architectural history lies in the form of the last kilometres from the mountains through a 200 metre deep valley to the Akropolis. The pipe consisted of three channels, which ended 3 km north of the citadel, before reaching the valley, and emptied into a pool, which included a double sedimentation tank. This pool was 35 metres higher than the summit of the citadel. The pipe from the pool to the Acropolis consisted of only a single channel - a lead pipe pressurised to 200 mH2O. The water was able to cross the valley between the pool and the citadel with the help of this pressurised conduit. It functioned as a communicating vessel, such that the water rose to the height of the citadel on its own as a result of the pressurised pipe.