Thucydides 2.45.1:  The Orphans

Simon Goldhill on the Great Dionysia, pp. 75ff:

Goldhill stresses the civic ritual of the tragic festival.  All business is abandoned, the courts are closed, the festival lasts five or six days, Athens is thronged with visitors.  The city itself chooses and pays the playwrights, elects the judges of the contest by lot, gives prizes. Processions, sacrifices, drinking, parties, surrounded the plays:  men and women (probably) attended them.

The tragedies themselves were embedded in a ceremony: a crown was awarded for civic duties, tribute was collected and deposited in the orchestra of the theater, war orphans who had come of age were paraded on stage in full armor, a herald delivered a speech on what the state has done for the boys, who are now citizens.   "This ceremony … marks the military aspect of the idea of citizenship … it marks the polis as educator and nourisher."  The obligations of the individual to the city, the sense of a citizen recognized by the city "publicly being shown to take on the role of citizen as adult, male, and hoplite [infantry soldier]."  This was a public display of civic ideology.

Then the plays that follow surprising seem to undermine secure communication and idealized justice, exploring problems and depicting a crisis in belief.