Pergamum or Pergamos, was an ancient city of western Anatolia in Asia Minor, now the modern village of Bergama, in Mysia, Turkey. It is located on a sharp rugged hill about 16 miles from the Aegean Sea alongside the Caicus River Valley. The acropolis, which is visible from a great distance, is accessible only from the southern slope. Archaeological excavations conducted by the German Archaeological Institute reveal that ancient Pergamum has been occupied since the second millennium BC. The first mention of the city in written history comes from around 400 BC in the work of the Greek soldier and writer Xenophon.