The memory of the Crusader occupation of the Levant did not die when the last Franks were driven from the Holy Land in 1291. The ideal of crusading remained alive into the fifteenth century and revived, in a rather different form, with the sixteenth-century wars between the Habsburgs and the Ottomans. Memories of lands held and lost were kept alive in Du Cange's Lignages d'Outremer, and the Cartulary of the Knights of St John survived as a witness of the properties they had once held. Even today there is a titular king of Jerusalem.

Nonetheless, acquaintance with surviving Crusader monuments was increasingly rare. The pilgrims of the late Middle Ages were concerned with finding the Holy Places not the traces of Frankish occupation, and the travellers of the seventeenth and eighteenth centuries, when they noticed ancient monuments at all, devoted their attention to Roman antiquities. It is especially frustrating that we have no detailed descriptions of Crusader castles before the Palestine earthquake of 1837 which did such damage at Chastel Pelerin and Saphet and the contemporary campaigns of Ibrahim Pasha in 1840 which resulted in extensive damage to Sidon, Chastel Pelerin, Saone and Antioch among others.

The scientific examination of Crusader castles was pioneered by Emmanuel Guillaume Rey (1837–1916). Rey's work was the product of a growing French interest in the Crusades in the first half of the nineteenth century. This had been stimulated by the publication in 1822 of Michaud's Histoire des Croisades and in 1829 of the same author's Bibliothèque des Croisades which included translations of Arabic chronicles by M. Reinaud.