Plato

He came from an aristocratic family and lived up to 80 years.
Creator of the Academy in Athens.
Learned mathematics from Pythogarus.

Many individuals influenced his thinking.
Socrates was his teacher.

Dialogue was his way of discussing a topic. His interests branched to philosophy, metaphysics, ethics, logics and religion.

His theory of form (physical word) and non form, most likely the behaviour of mind and abstract thinking lead to the foundation of Western philosophy, which the modern scholars still discuss to present day.

He left behind volumes of writing and most of them were probably came down from the interpretation of Socrates thinking.
His earlier writings are supposed to be coming form his teacher Socrates but in his later life probably after the death of his teacher, he was critical of his teacher and made his own line of thinking.

He is known as the student becoming the teacher.

Founding of the Academy and preservation of thinking that predated him was his monumental contribution to philosophy to begin with but later branched in to other disciplines in education.

His efforts of educating, the human mind by dialogue continues.