Plato (/ˈpleɪtoʊ/ PLAY-toe; Greek: Πλάτων), born Aristocles (Ἀριστοκλῆς; c. 427 – 348 BC), was an ancient Greek philosopher of the Classical period who is considered a foundational thinker in Western philosophy and an innovator of the written dialogue and dialectic forms. He raised problems for what became all the major areas of both theoretical philosophy and practical philosophy, and was the founder of the Platonic Academy, a philosophical school in Athens where Plato taught the doctrines that would later become known as Platonism.