Free will in antiquity
In Plato's Gorgias (and in the Protagoras 345c4-e6), Socrates argues that no one does wrong willingly, one of the most famous doctrines to be associated with him. When framed in modern (Western) terms, the implication is that it is ignorance, rather that free individual agency, that is responsible for morally wrong actions.
Plato's tripartite theory of soul
In Book IV of the "Republic", Socrates and his interlocutors (Glaucon and Adeimantus) are attempting to answer whether the soul is one or made of parts. Socrates states that, "It is clear that the same thing will never do or undergo opposite things in the same part of it and towards the same thing at the same time; so if we find this happening, we shall know it was not one thing but more than one." (This is an example of Plato's Principle of Non-Contradiction.) For instance, it seems that, given each person has only one soul, it should be impossible for a person to simultaneously desire something yet also at that very moment be averse to the same thing, as when one is tempted to commit a crime but also averse to it. Both Socrates and Glaucon agree that it should not be possible for the soul to at the same time both be in one state and its opposite. From this it follows that there must be at least two aspects to soul.