Peter Abelard (1079-1142) is one of the great historical philosophers and ranks among the top five philosophers of the medieval period. A Christian philosopher, theologian and logician, Abelard quickly gained fame as a great mind in the late eleventh century in France. His intellect, combined with his appetite for argument, led him to public disputes with many of his teachers. He was particularly concerned to refute the philosophical doctrine of realism and replace it with his own conceptualist doctrine.