In 1204, a Constantinopolitan monk named Brother Konstantinos made what he believed was a righteous choice — destroying what he thought were pagan corruptions hidden in the imperial library. He was catastrophically wrong about which scrolls he grabbed, and that mistake sent a handful of terrified scholars fleeing west with armloads of texts that would detonate the Renaissance. This is the story of how one man's fanaticism, a borrowed donkey, and a leaky boat in the Bosphorus gave Europe Plato, Euclid, and Archimedes — all at once.