History of the Peloponnesian War

He gave them advice also on their present affairs, the same as he had before given; namely, to prepare for the war, and bring in their property from the country, and not go out against them to battle, but to come in and guard the city, and get ready their fleet, in which they were so strong, and keep the allies tight in hand; reminding them that their main strength was derived from the returns of the money paid by these, and that most of the advantages in war were gained by counsel and abundance of money.

And [on this head] he told them to be of good courage, as the state had, on an average, six hundred talents coming in yearly as tribute from the allies, not reckoning its other sources of income; while there were still at that time in the Acropolis 6000 talents of coined silver;