In 1518, as a storm of opposition raged around him, Luther received a letter from Dr. Johannes Eck. Eck was the chair of theology at Inglostadt University near Munich. The two men had exchanged a number of letters discussing the need for reform within the church over the preceding years and they had developed a friendship. However, despite the rapport they had built, Eck was appalled when he read Luther's work on the 95 Theses and the subsequent other booklets he published in defence of it.
Eck, believing that Luther needed a course correction, sent him a rebuttal to the 95 Theses. Interestingly Eck's rebuttal consisted of a dagger, drawn beside each of the points within the theses that Eck took issue against. While Eck insisted that he did not want to cause a public spectacle, he did offer to take up the invitation implicit in Luther's theses to dispute the points that Luther had raised.
After looking for a suitable venue and sponsors who were willing to risk their reputations and quite possibly their necks by hosting such a debate, Eck finally managed to convince the University of Leipzig to host a debate between himself and Luther.