Pope Leo X issues the bull Cum postquam which defends indulgences as a treasury of merits, from which popes may make withdrawals to be applied to the spiritual accounts of believers, remitting their temporal suffering in Purgatory and speeding their way to Heaven.
In the previous year the Augustinian monk and Wittenberg professor Martin Luther issued his 95 Theses attacking the doctrines of Purgatory and indulgences. Angered by the papally-approved sale of indulgences in eastern Germany by the Dominican monk Johann Tetzel, Luther proclaimed “I say that no one can prove by a single word of Scripture that divine justice desires or demands any sort of suffering or satisfaction from the sinner other than his heartfelt and genuine sorrow or conversion, with the intention to bear the cross of Christ from now on …” The resulting brouhaha we call the Protestant Reformation.
It was unfortunate for the Catholic Church that Leo, born Giovanni di Lorenzo de’ Medici, son of Lorenzo the Magnificent of Florence, was its ruler at the time of this controversy. He was not even a priest until his election as pope; he was a patron of the arts but no shepherd of souls.