Pergamon or Pergamum (was an ancient Greek city in modern-day Turkey, in Mysia, north-western Anatolia, 16 miles from the Aegean Sea, located on a promontory on the north side of the river Caicus, that became the capital of the Kingdom of Pergamon during the Hellenistic period, under the Attalid dynasty, 281–133 BC. Today, the main sites of ancient Pergamon are to the north and west of the modern city of Bergama.