Martin Luther OSA (German: [ˈmaɐ̯tiːn ˈlʊtɐ] ( ); 10 November 1483 – 18 February 1546) was a German friar (Observant Augustinian), Catholic priest, professor of theology and seminal figure of the 16th-century movement in Christianity known later as the Protestant Reformation. He strongly disputed the claim that freedom from God's punishment for sin could be purchased with monetary values. He confronted indulgence salesman Johann Tetzel, a Dominican friar, with his Ninety-Five Theses in 1517. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the Pope and condemnation as an outlaw by the Emperor.