In the summer of 1518, legal proceedings in church courts began against Luther for his criticism of indulgences, as was standard procedure for clerics who were subject to ecclesiastical jurisdiction rather than civil jurisdiction. As a result, an order was issued for Luther to stand trial in Rome. However, Rome lifted that requirement, paving the way for his interrogation on German soil. The counselor appointed for that case was the Dominican cardinal and papal legate Tomas de Vio, named Cajetan for his Italian hometown of Gaeta. Cajetan was a theologian and ecclesiastic of high standing. He had published an extended commentary of Aquinas’ Summa, eventually became vicar general of the Dominican Order, and delivered an address at the opening of Lateran V in 1512. Cajetan was a committed Thomist with a high view of papal authority and the clash with Luther was inevitable.
Frederick the Wise, Luther’s prince and the benefactor of the university at Wittenberg, had arranged for the accused’s safe conduct to Augsburg and a fair hearing from Cajetan. The hearing itself was held in the home of the famous Fugger bankers, whose loan to Leo X for the building of St. Peter’s was the cause for the increased sale of indulgences. Cajetan was directed by Rome neither to debate Luther, nor make a final judgment on his theology, but rather to insist that he recant by saying the simple word revoco—“I recant.” Upon arrival, Luther followed the advice of his colleagues and prostrated himself before Cajetan, then rose to his knees to answer the cardinal’s interrogation. Luther, however, refused to recant his positions and instead pressed Cajetan for clarity on where he was in error. Over the course of the three meetings on consecutive days from October 12-14, the theologically erudite cardinal was unable to resist debate with Luther.
The central point of contention Cajetan had with Luther was the authority of the papacy to issue indulgences. Cajetan repeatedly cited Aquinas and the bull Unigenitus, promulgated by Clement VI in 1343 in support of indulgences, to validate his position. Luther rejected the authority of Aquinas and claimed the pope had no authority to institute a dogma teaching justification through any means other than Christ. When Cajetan pressed him on the point, Luther responded that pope, council, and theologian can all err, appealing to numerous medieval theologians and even canon law in support of his argument. With each passing day of the hearing, the situation grew increasingly tenser and ultimately resulted in Cajetan sending Luther on his way with the demand to recant or face the consequences, presumably imprisonment and deportation to Rome.
After the heated final session, Cajetan implored both Johannes von Staupitz, Luther’s Augustinian superior, and Wenceslaus Link, his Saxon legal counsel, to extricate a repudiation from Luther, but they were unsuccessful. Realizing the gravity of the situation, Staupitz absolved Luther of his vow of obedience and thus freed himself from responsibility for Luther’s teaching, leaving the young monk with the words, “You should bear in mind, brother, that you began this in the name of Jesus Christ.” With that, Luther proceeded with his cause and made an appeal to a future council to resolve the issue—a plight specifically forbidden in the 1460 papal bull Execrabilis, but one he and other Germans had availed themselves of variously over the years and would continue do so until the convocation of the Council of Trent in 1545.