"The rhinoceros, that is, any powerful man, is bound with a thong so that he may crush the clods of the valleys, that is, the oppressors of the humble."--Odo of Cluny, Vita Geraldi i.8

To the second abbot of the great monastery at Cluny, Saint Odo, tenth-century Europe was a world filled with violent men oppressing at whim the poor and the powerless. As royal authority waned, local magnates, unrestrained by any authority, divine or human, seized the opportunity to enhance their positions. Odo, along with Cluny's other founding spiritual and ideological leaders, created within...