Seizing the Hungarian throne at the age of fifteen, Matthias Corvinus, the "Raven King," was an effervescent presence on the fifteenth-century stage. A successful warrior and munificent art patron, he sought to leave as symbols of his strategic and humanist ambitions a strong, unified country, splendid palaces, and the most magnificent library in Christendom. But Hungary, invaded by Turkey after Matthias's death in 1490, yielded its treasures, and the Raven King's exquisite library of two thousand volumes, witness to a golden cultural age, was dispersed first across Europe and then the...