As dissension mounted between the rival Arab dynasties in Baghdad, Cordoba, and Cairo, Christendom rallied to oppose the Muslims in Spain and Jerusalem. This program plots out the decline of the Empire of the Caliphate and the acquisition of Arab knowledge by Europeans starved for Islam's intellectual riches. The rise of feudalism and papal authority, the gradual defeat of the Muslim rulers in Spain, the Seljuk usurpation of Abbasid power in the Near East, and the Crusades are explained, along with the concerted efforts of Catholic authorities to translate the vast libraries of Arab scientific and philosophic texts.