In 587 a.d., two monks set off on an extraordinary journey that would take them in an arc across the entire Byzantine world, from the shores of the Bosphorus to the sand dunes of Egypt. On the way John Moschos and his pupil Sophronius the Sophist stayed in caves, monasteries, and remote hermitages, collecting the wisdom of the stylites and the desert fathers before their fragile world finally shattered under the great eruption of Islam. More than...