Leo X.

Leo X., Giovanni de' Medici, son of Lorenzo the Magnificent, sovereign of Florence; was distinguished as a patron of art, science, and letters, and as occupant of the chair of St. Peter at the outbreak of the Reformation, and as by his issue of indulgences for the replenishment of his treasure provoking the movement and rousing the ire of Luther, which set the rest of Europe on fire.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)