"Gregorovius believed that through the dialectical conflict between the forces of the papacy and the empire in medieval Rome the birth of European culture was accomplished, and mankind progressed toward greater spiritual liberty. For this volume Professor Morrison has selected excerpts from the History of the City of Rome in the Middle Ages which 'show how, in Gregorovius's view, the cosmic drama of this eternal progress was played out in the institutions and cultural achievements of medieval Rome.'" -- Cover page 4.