Peter Abelard (1079-1142) was one of the early pioneers of textual criticism in 12 century Paris. During his studies he discovered contradictions among the writings of St. Augustine, St. Clement and the other church fathers. These apparent contradictions he compiled into a compendium of excerpts he called Sic et Non.

Abelard wrote Sic et Non at first in answer to the Islamic accusation that Christianity is contradictory, because the writings of different church leaders all differed and therefore contradicted each other.

Abelard identified the contradictions and identified how to resolve the contradictions. He also tried to reconcile differences between two different sources by showing the use of figurative language might assume different facts. He was then able to establish the intergrity of church traditions.

Abelard is also famous for his love affair with Heloise, detailed in The Letters of Abelard and Heloise.