Pergamon, Pergamum or Pérgamo was an ancient Greek city in modern-day Turkey, in Mysia, today located 160 miles (260 km) from the Aegean Sea on a promontory on the north side of the river Caicus (modern day Bakircay), 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.