Philetaerus enjoyed considerable autonomy

Philetaerus, especially after the death of Seleucus, enjoyed considerable autonomy despite being nominally under the Seleucids. He acquired considerable wealth because Pergamon had been the treasure-hold of Lysimachus and extended his power and influence beyond Pergamon. He contributed troops, money, and food to the city of Cyzicus, in Mysia, for its defense against the invading Gauls, thus gaining prestige and goodwill for him and his family.