If you were designing a prayer book for a teenage boy, what would you include? What if that boy was poised to become one of the most powerful people in the world? The prayer book of Charles V was custom-made to prepare the young man to rule—and rule well. So what do we find in its pages? Tales of derring-do? Stirring stories of victory? Not at all. We find image after image of suffering and humility. One such example is an image of Jesus being crushed in a wine press. This common image from that time represented his sacrifice for humanity’s sin. Written in Latin are the words of Isaiah 63:3, “I have trodden the winepress alone.” It suggests to the young prince that he too would face crushing burdens as a ruler and should expect to bear them for the sake of others. Perhaps the most intriguing illumination is the final one, which shows the Byzantine emperor Heraclius entering Jerusalem. According to a popular story, the Persians stole the cross on which Jesus was crucified and Heraclius won it back. When he attempted to enter Jerusalem in a splendid procession, an angel blocked his way. “When the King of heaven passed through this gate to suffer death,” said the angel, “there was no royal pomp.” The emperor wept, stepped down from his horse, took off his boots and royal regalia, and carried the cross humbly through the gate. Given the extraordinary expense and craftsmanship of a prayer book such as this, each image would have been carefully chosen to make a point. The point here is clear: the greatest leaders are humble, pious, and willing to sacrifice themselves. The prayer book of Charles V is not only a remarkable work of art, it shows how stories of the Bible, and stories based on the Bible, could have shaped the moral imagination of a young man destined to rule two empires.