December 10, 1520 - Pope Leo X has issued the papal bull "Exsurge Domine" (Latin: Arise O Lord), condemning 41 of Martin Luther's 95 theses as heresy. Luther is threatened with excommunication unless he recants within a 60-day period.
Luther responded on December 10 by publicly burning the bull in Wittenberg. He explained his actions: "Since they have burned my books, I burn theirs. ... Seldom has the pope overcome anyone with Scripture and with reason."
Luther was excommunicated less than 30 days later, putting Europe on an irrevocable course toward the Reformation and the destruction of the Roman Catholic Church's power over daily life on the continent.