Its principal tributaries are - the Phrygius (Kum Chai), which receives the waters of the Lycus (Giirduk Chai), and the Cogamus (Kuzu Chai), which in its upper course is separated from the valley of the Maeander by hills that were crossed by the Roman road from Pergamum to Laodicea.
For about 46 years they were the scourge of the western half of Asia Minor, ravaging the country, as allies of one or other of the warring princes, without any serious check, until Attalus I., king of Pergamum (241-197), inflicted several severe defeats upon them, and about 232 B.C. forced them to settle permanently in the region to which they gave their name.
The earliest zeal has passed away and heathen ways of thought and life are tolerated and practised at Pergamum and Ephesus, and faith is dying or dead at Laodicea and Sardis.
By Macrinus he was entrusted with the administration of Pergamum and Smyrna; and on his return to Rome he was raised to the consulship about 220.
This far from exhausts the external activity of the nation and the government: the establishment of studentships for the study of oriental languages enabled Germans to make their way in the Turkish and Persian empires, and to open up a fresh market for German goods; by the great excavations at Pergamum and Olympia Germany entered with great distinction on a field in which the way had been shown by France and Great Britain.
The kingdoms of Numidia, Macedonia, Syria and Pergamum were examples of protected states, their rulers being termed inservientes.
Athena Polias was the patron-goddess of Pergamum, and the legend combines the ethnological record of the connexion claimed between Arcadia and Pergamum with the usual belief that the hero of the city was son of its guardian deity, or at least of her priestess.
Antiochus of Commagene instituted an order of priests to celebrate the anniversary of his birth and coronation in a special sanctuary, and the kings of Pergamum claimed divine honours for themselves and their wives during their lifetime.
The German Archaeological Institute, founded in 1874, has carried out excavations at Thebes, Lesbos, Paros, Athens and elsewhere; it has also been associated in the great researches at Olympia, Pergamum and Troy, and in many other important undertakings.
Among the first of these benefactions was the great gymnasium of Ptolemy, built in the neighbourhood of the Agora about 250 B.C. Successive princes of the dynasty of Pergamum interested themselves in the adorn western entrance being the well-known Doric portico of Athena Archegetis with an inscription recording its erection from donations of Julius Caesar and Augustus.