Canon law served the church just as civil law supported a secular government. It defined the rights, duties and powers of all people and priests within the church. It was the law administered in all ecclesiastical courts, from those of the bishop up to that of the pope.

Sometime around 1140 Gratian, a monk of the monastery of St. Felix at Bologna, published a Harmony of Discordant Canons which tried to coordinate all previous collections of church law. Since he arranged his quotations of authorities subject by subject, his Harmony soon emerged as the sole manual for teachers and for judges in the church. But it also directed man's most intimate relationships. By virtue of its concern with baptism it established standards for all births — and all that led to births. The first inviting smile between man and woman brought the couple under its watchful shadow. It directed penance