Academy, school founded by Plato near Athens c.387 B.C. It took its name from the garden (named for the hero Academus) in which it was located. Plato's followers met there for nine centuries until, along with other pagan schools, it was closed by Emperor Justinian in A.D. 529. The Academy has come to mean the entire school of Platonic philosophy, covering the period from Plato through Neoplatonism under Proclus. During this period Platonic philosophy was modified in various ways. These have been frequently divided into three phases: the Old Academy (until c.250 B.C.) of Plato, Speusippus, and Xenocrates; the Middle Academy (until c.150 B.C.) of Arcesilaus and Carneades, who introduced and maintained skepticism as being more faithful to Plato and Socrates; and the New Academy (c.110 B.C.) of Philo of Larissa, who, with subsequent leaders, returned to the dogmatism of the Old Academy.