Antigone

Antigone tries, unsuccessfully, to persuade her sister Ismene to commit civil disobedience.

Antigone details the end of three of Oedipus' four children.  His sons Eteocles and Polynices fought in single combat over the rule of Thebes, and neither survived.  Eteocles, as the champion of Thebes, was given a "state" burial, but Polynices (who raised an army against Thebes) was to be denied any sort of rite by order of the new king of Thebes, Creon.  Antigone, distraught at Creon's order,  buried him anyway with a thin layer of dust.  Creon has him exhumed and his body re-exposed.  Antigone buries him again, but is caught this time.  Creon sentences her to spend the rest of her life walled in a cave.  Creon is eventually persuaded to let her out by the Chorus under threat of the gods wrath.  He arrives too late, Antigone has hung herself.  Creon's son and Antigone's fiance, Haimon, kills himself upon seeing Antigone dead.  Creon's wife upon hearing the news of her son's death, commits suicide and Creon ends the play regretting everything.

Antigone's an important work of Grecian political philosophy, even if that was not its purpose.  Creon argues for a very strong view of the state, one in which the king literally is the state.  To disobey his orders are to disrespect him, but to harm the very fabric of society.  He takes Antigone's disobedience as an attack against the state and brands her a traitor.  In the end, Sophocles makes it very clear this is not the most virtuous way of running a state.  That the state's leaders are held to a higher power, the rules set forth by the gods.

Antigone also establishes another theory of relations between the citizen and the state, that a citizen can be justified in purposefully flaunting the state's rules when the rules conflict with a higher standard.  Sophocles telling makes it clear that Antigone was doing what is right by ignoring Creon's order.  She was a hero to the citizens of Thebes (even if she was a rather tragic one) because she upheld a much higher standard than that of Creon.