Johann Eck became involved in a literary contest with Andreas Karlstadt and challenged his adversary to a public debate. In Leipzig, although the faculty of the university entered a protest, and the Bishops of Merseburg and Brandenburg launched prohibitions and an excommunication, the disputation took place under the ægis of Duke George of Saxony. Eck came to Leipzig with one attendant; Luther and Karlstadt entered the city accompanied by an army of adherents, mostly students. From 27 June to 4 July (1519) Eck and Karlstadt debated the subject of free will and our ability to cooperate with grace. Eck forced his antagonist to make admissions which stultified the new Lutheran doctrine, whereupon Luther himself came forward to assail the dogma of Roman supremacy by divine right. The debate on papal primacy was succeeded by discussions of purgatory, indulgences, penance, etc. On 14 and 15 July, Karlstadt resumed the debate on free will and good works. Finally, Duke George declared the disputation closed, and each of the contendents departed, as usual, claiming victory.