" Every person who is Fountain-blessed demonstrates a remarkable power, and sometimes more than one. They keep their lore secret from the world, except for some general principles that I will speak on. The terms used to describe the two major ways in which they draw in power are “rigor” and “vigor.” The term “rigor” implies severity and strictness. The magic comes through meticulous and persistent adherence to some regimented craft or routine. These individuals are iron-willed and self-disciplined to a degree very uncommon amongst their fellows. The term “vigor” implies effort, energy, and enthusiasm. To do a task out of the love of it, not for ambition’s sake alone. These two concepts mark the twin horses by which the magic of the Fountain can be drawn. Why one individual may prefer one to the other or whether there is difference in the efficacy of these methods remains, to the rest of us, a mystery.   —Polidoro Urbino, Court Historian of Kingfountain "

― Jeff Wheeler , The Thief's Daughter (Kingfountain, #2)