12 Cassino, as all know, was the chief dwelling place and the main theater of the Holy Patriarch's virtue and sanctity. From the summit of this mountain, while practically on all sides ignorance and the darkness of vice kept trying to overshadow and envelop everything, a new light shone, kindled by the teaching and civilization of old and further enriched by the precepts of Christianity; it illumined the wandering peoples and nations, recalled them to truth and directed them along the right path. Thus indeed it may be rightly asserted that the holy monastery built there was a haven and shelter of highest learning and of all the virtues, and in those very troubled times was, "as it were, a pillar of the Church and a bulwark of the faith".
Source: Fulgens Radiatur (Vatican.va)