History of the Peloponnesian War

Of all the causes of defection, that connected with arrears of tribute and vessels, and with failure of service, was the chief; for the Athenians were very severe and exacting, and made themselves offensive by applying the screw of necessity to men who were not used to and in fact not disposed for any continuous labour.

In some other respects the Athenians were not the old popular rulers they had been at first; and if they had more than their fair share of service, it was correspondingly easy for them to reduce any that tried to leave the confederacy.

For this the allies had themselves to blame; the wish to get off service making most of them arrange to pay their share of the expense in money instead of in ships, and so to avoid having to leave their homes. Thus while Athens was increasing her navy with the funds which they contributed, a revolt always found them without resources or experience for war.