Why do you think Aristotle's theories started replacing Plato's in the 13th century? or at any time?

I had to do a little research for your question, but what i found is that though Aristotle was a student of Plato's, Aristotle became more popular due to St. Thomas who reprised Aristotles views. Here's a link that gives more info on all three, Plato, Aristotle, and Thomas