Finances
The economic resources of the Athenian State were not excessive. All the glory of Athens in the Age of Pericles, its constructions, public works, religious buildings, sculptures, etc. would not have been possible without the treasury of the Delian League. The treasury was originally held on the island of Delos but Pericles moved it to Athens under the pretext that Delos wasn't safe enough. This resulted in internal friction within the league and the rebellion of some city-states that were members. Athens retaliated quickly and some scholars believe this to be the period where we should talk about an Athenian Empire instead of a league.
Other small incomes came from customs fees and fines. In times of war a special tax was levied on rich citizens. These citizens were also charged permanently with other taxes for the good of the city. This was called the system of liturgy. The taxes were used to maintain the triremes which gave Athens great naval power and to pay and maintain a chorus for big religious festivals. It is believed that rich Athenian men saw it as an honor to sponsor the triremes (probably because they became leaders of it for the period they supported it) or the festivals and they often engaged in competitive donating.
Read more about this topic: Fifth-century Athens