Although medieval scholars knew important classical authors such as virgil and cicero, the works of were not fully known in western europe until the renaissance.

Medieval scholars knew classical authors like Virigil and Cicero, but the works of Plato were not fully known throughout Western Europe until the Renaissance. 
The Medieval period was also known as the dark ages, it was the time that knowledge were limited on the bible and the clergy. These clergymen serve as the teachers of the people. As the period progress the thirst for knowledge grew and this has led to the Renaissance, where people can freely read anything they want, much knowledge from the East were brought from Constantinople, where Ancient knowledge on the works of people like Plato was still preserved.