Answer: Obviously, Luther was considered to be heretic and was summoned to defend his theses.
Explanation: Luther, "the little monk" from Germany threatened the profitable system of indulgences and the Roman Catholic Church had to respond.
Luther was subsequently called to debate high-ranking Catholic theologians, such as Cardinal Cajetan in Augsburg (1518) and Johann Eck in Leipzig (1519) and surprised everyone with his refusal to change his views.
On the contrary, Luther even expanded his critique of the church in Rome with three major pieces in 1520. In these important documents, Luther publicly questioned the infallibility and authority of the Pope, critiqued central Roman Catholic doctrines, and he defended the priesthood of all believers. Of course, the Pope was not amused. In his papal bull, Exsurge Domine, he declared that Luther was a “wild boar that had invaded the Lord’s vineyard,” and called Luther to recant his views. Not intimidated at the slightest, Luther burned the bull and was subsequently excommunicated.
