12th Century: Saladin (c. 1138-1193)

When Dante Alighieri compiled his great medieval Who's Who of heroes and villains, the Divine Comedy, the highest a non-Christian could climb was Limbo. Ancient pagans had to be virtuous indeed to warrant inclusion: the residents included Homer, Caesar, Plato and Dante's guide, Vergil. But perhaps the most surprising entry in Dante's catalog of "great-hearted souls" was a figure "solitary, set apart."

That figure was Saladin. It is testament to his extraordinary stature in the Middle Ages that not only was Saladin the sole "modern" mentioned--he had been dead barely 100 years when Dante wrote--but also that a man who had...