Historical events include lessons of good and bad behaviors of human beings.To discover these lessons,we must generalize the historical event by the basic attributes,so that we can notice the underlying patterns that commonly occur in multiple historical events.Based on this viewpoint,we have developed a learning system that supports the generalization of historical events based on the basic attributes and helps finding lessons by comparing common patterns from two generalized events.In this paper,the effect of our system is discussed based on the experimental result.