Plato was a student of Socrates. He wrote down Socrates' teachings in dialogue form. He focussed on collective action, your faults and others' faults. He was a critic of democracy, in his book, The Rebublic, he desribes a new government type that has a philosopher as king, the next social class was the educated people, and the third were the regular citizens. His school was The Academy, he teaches Aristotle here.