War and Peace in the earlier Middle Ages

Men of the earlier Middle Ages knew what they meant by war and peace. Their definitions are not hard to find, even though, when found, they prove to be inconsistent. They knew that there were just and unjust wars, good kinds of peace and bad, and they could envisage war and peace as two poles of a single concept. My intention is not to survey this large and ramshackle field but simply to enquire how far some of the definitions tallied with the facts of war and peace; and whether, at the end, the pressures making for peace had affected the nature of war. To ask whether Western Europe in the days of King Alfred and the later Carolingians was more or less peaceful than it had been four centuries earlier is not very meaningful, since an entirely new situation was created by the attacks of the Vikings, Arabs and Magyars; but it is meaningful to ask whether four centuries of additional experience had caused men to look at war and peace in a different way.