Plato 
Apology [PDF ebook] 

The Apology of Socrates, by Plato, is the Socratic dialogue that presents the speech of legal self-defence, which Socrates presented at his trial for impiety and corruption, in 399 BC.
Specifically, the Apology of Socrates is a defence against the charges of "corrupting the youth" and "not believing in the gods in whom the city believes, but in other daimonia that are novel" to Athens (24b).
Among the primary sources about the trial and death of the philosopher Socrates (469–399 BC), the Apology of Socrates is the dialogue that depicts the trial, and is one of four Socratic dialogues, along with Euthyphro, Phaedo, and Crito, through which Plato details the final days of the philosopher Socrates.
The Apology of Socrates begins with Socrates addressing the jury to ask if the men of Athens (the jury) have been persuaded by the Orators Lycon, Anytus, and Meletus, who have accused Socrates of corrupting the young people of the city and of impiety against the pantheon of Athens. The first sentence of his speech establishes the theme of the dialogue — that philosophy begins with an admission of ignorance. Socrates later clarifies that point of philosophy when he says that whatever wisdom he possesses comes from knowing that he knows nothing (23b, 29b).
In the course of the trial, Socrates imitates, parodies, and corrects the Orators, his accusers, and asks the jury to judge him by the truth of his statements, not by his oratorical skill (cf. Lysias XIX 1, 2, 3; Isaeus X 1; Isocrates XV 79; Aeschines II 24). Socrates says he will not use sophistic language — carefully arranged ornate words and phrases — but will speak using the common idiom of the Greek language. He affirms that he will speak in the manner he is heard using in the agora and at the money tables. Despite his claim of ignorance, Socrates speaks masterfully, correcting the Orators and showing them what they should have done — speak the truth persuasively and with wisdom. Although offered the opportunity to appease the prejudices of the jury, with a minimal concession to the charges of corruption and impiety, Socrates does not yield his integrity to avoid the penalty of death. Accordingly, the jury condemns Socrates to death.