During the 14th century, Johannes Klenkok opposed the Sachsenspiegel with a writing known as the "Decadicon" because he considered several articles of the law book to contradict the Corpus Juris Canonici. Following a written debate, Klenkok turned to his former disciple, French canonist, and cardinal of the Curia in Avignon, Pierre de la Vergne. In the end, Pope Gregory XI condemned 14 articles with his papal bull "Salvator Humani Generis" that was issued in 1374, but this did not reduce the success of the Sachsenspiegel.