Martin Luther published his 95 Theses in 1517 as an invitation to academic debate about the selling of indulgences by priests like Johan Tetzel. The Theses criticized the Church's position that indulgences absolve sins and ensure salvation. While Luther did not intend a split from the Church, his arguments questioning the authority of the Pope and Church traditions moved in a heretical direction. After the Theses spread widely, Luther was summoned by Church authorities but refused to recant his positions that challenged the Church's power over salvation and interpretation of scripture.