Gratian and His Book: How a Medieval Teacher Changed European Law and Religion

Gratian of Bologna, later bishop of Chiusi (died c. 1145), was a remarkably influential lawyer, who is undeservedly little known today. He was a legal expert who specialized in the rules and regulations of the Western Christian church. In around 1140, he put together a law book known as the Decretum, which became a great success, remaining foundational for medieval and modern law. The article focuses on three legal areas: tithes, marriage, and natural law. It discusses how Gratian used scholastic methods and classroom exercises to come to grips with the many contradictions that existed in the more than ten centuries of law that he strove to collect and synthesize. It highlights how Gratian’s innovations in marriage law, natural law, and procedural law still influence modern law. Gratian left Bologna before he had finished the course, and the article reflects on the differences in his later fate and that of his book.