A study of the three great religions/civilizations of the Mediterranean region in the middle ages-Islam, Byzantine Christianity, and western Christianity-from about 400-1500, focusing on their basic beliefs and religious practices, and their economic, social, political, and cultural characteristics. It also studies the points of contact and conflict among the civilizations, including the crusades, the Reconquista, and the Islamic intellectual influence on Western Europe through Sicily and Spain. The role and experience of the Jews through the centuries are also explored. HA