It is not Islamic civilization preserved the works of Plato, Socrates and Aristotle. It is the Romans. Coz Romans defeated the Greeks in around 500 BC but didn't destroy what they had. In fact, they even copied and acknowledged the Greeks and their culture. And Muslims in Europe were far later than the fall of the Romans. Roman empire in the West was destroyed by the Barbarians from the north, mostly Germans (around 100 AD) and in the East until the defeat of Constantinople by the ottoman Turks (around 1400 AD). Renaissance was a period in the western history before or in the beginning of the so called modern history and after the Medieval ages or the so called dark ages. It is between or around 1400 AD to 1600 AD.