In exchange for his aid, Satan demanded that Theophilus renounce Christ and the Virgin Mary in a contract signed with his own blood.

The bishop burned the document, and Theophilus died out of sheer joy to be free from the burden of his contract.

[1] Theophilus's story played a role in establishing the importance of the intercession of the Virgin Mary, in addition to providing a basis for later tales involving the conjuration of devils.

The story was used to illustrate the power and necessity of her intercession by Peter Damian, Bernard of Clairvaux, Anthony of Padua, Bonaventure and much later on by Alphonsus Liguori.

The legend was the most popular in art in the 13th century; it occurred most frequently in illuminated manuscripts[9] and stained glass.

[8] This legend is the only non-biblical Marian story consistently depicted in sculpture and glass in French cathedrals during this time.