⁶ Ira M. Lapidus, A History of Islamic Societies, Cambridge, Cambridge University Press, 1988, págs. 41-42; princesa Anna Comnena, citada en Karen Armstrons, Holy War: The Crusades and Their Impact on Today's World, Nueva York, Doubleday-Anchor, 1991, págs. 3-4, y en Arnold J. Toynbee, Study of History, Londres, Oxford University Press, 1954, VIII, 390.<<