What Is the Major Contribution of Plato?

The Republic, a philosophical work produced in 380 BCE and still discussed in modern curriculum, is one of the more commonly known contributions of Plato. The Republic addresses justice and politics. Another contribution of Plato is The Academy, an institution at which students could study astronomy, biology, mathematics and politics.
Many scholars accredit The Academy as the first university founded in Europe. The Academy was founded in 385 BCE, and, with the exception of a period of house arrest, Plato oversaw the institution until he died. Legend tells that the name of the school was derived from the name of the hero for which the land on which it was built: Academos. Unfortunately, when the emperor Justinian came to power he felt that it promoted paganism. So the institution was closed in 529 CE.