My source book for this discussion is The Emergence of the Catholic Tradition by Jaroslav Pelikan. Professor Pelikan was an eminent scholar in the history of the Catholic Church and Professor of Ecclesiastical History at Yale from 1972-1996. He wrote a five volume set on the Catholic tradition including the work cited above which serves as volume one.
Pelikan cites the closing of the Greek philosophical school by Justinian in 529 A.D. as the triumph of the church over pagan philosophy. Or as Gibbon put it,
“this was a time when Christian theologians superseded the exercise of reason, resolved every question by an article of faith, and condemned the infidel or skeptic to eternal flames.”