In the "Phaedrus" Plato(427-347 B.C.) is concerned with establishing the principles of rhetoric.
Through the mouths of Socrates and Phaedrus he argues that rhetoric is only acceptable as an art when it is firmly based on the truth inspired by love, the common experience of true philosophic activity. It is in this dialogue that Plato employs the famous image of love as the driver of the chariot of souls.
The seventh and eight letters (which are accepted as genuine amongst those attributed to Plato) provide fascinating glimpses into the contemporary power struggle in Sicily and evidence his failure to put into practice his theory of philosopher-king.