ABSTRACT
Gratian’s Decretum is a foundational text for medieval legal science in general and for the history of canon law specifically. The pivotal change came in the twelfth century, when the idea that consent makes marriage entered the mainstream of European law. This happened through Pope Alexander III’s precedent-setting decisions in the 1170s. He decided that marriage comes about when two persons consent to marry each other. Gratian 1 may have compromised between the consent theory and the coital theory of marriage formation, but he nevertheless emphasised consent. The efficient cause of marriage, he said, is consent, immediately before quoting the classic line, ‘Consent makes marriage.’ Gratian 1 confronted the rights of unfree persons to marry head on. As was his habit, he began his treatment of the issue with a brief hypothetical case. A young noblewoman contracts via intermediaries to marry a nobleman whom she has never met.
