Plato's Apology

Socrates consumes the hemlock that kills him after the events of the Apology

Plato wrote the Apology to serve either as a historical account of his teacher's defense for charges of impiety and corrupting the youth of Athens.  Long a thorn in the side of Athenians, three prominent Athenians have arranged for Socrates to face trial in hopes of his removal from the Athenian scene (by execution or by exile).  Plato divides his story into three parts, Socrates' defense, his setnencing, and his reaction to his death sentence.  Socrates lays out his case that he is not an atheist, nor has he corrupted the youth of Athens.  He does this while countering a particular accuser, Meletus, and outlining the contradiction of Meletus reasoning.    Socrates also makes his case for why he is not afraid.  Death is either an eternally long and peaceful sleep or a chance to question the dead heroes of Greek culture, both of which he looks forward to.  He is also worried only about doing good.  Eventually he is found guilty of his crime, and counters the prosecution's proposed punishment of death by asking to be set up in what is essentially a penthouse suite that is typically reserved for the victors of the Olympics.  It is no surprise that the jury is upset with his intransigence and decide to sentence Socrates to death.  He accepts his fate, reiterates that he is not afraid of death and that he has acted not out of self-preservation but only for the good, as he should have.

The most striking part of the Apology is when Socrates is describing death.  He doesn't fear it as it will either be the longest and best sleep or a chance to continue doing what he loves doing, pestering people with his questions.  It's a very strange take on death that is different from the view most have of it.  His view on the importance of doing good even in the face of death is not, and is a consistent theme of Greek literature (see Antigone, who does right by the gods even though it leads to her death).  

Whether this is an accurate tale of what transpired during Socrates' trial or not is unknown, but it doesn't alter the philosophy outlined (either as Socrates' own or Plato's in Socrates' mouth) if it was written just to discuss death and goodness.