For more than eight decades, scholarly interest in the Burgundian abbey of Cluny has focused on the first 250 years of the monastery’s history, from its founding in 910 on the site of what had once been a Roman villa through the reign of its influential twelfth-century abbot Peter the Venerable (d. 1156). It is thus intriguing to find Janet Marquardt focusing instead on aspects of the abbey’s demise and recovery during the restoration of...