Our best fund for the history of Jerusalem from Heraclius to the crusades is contained in two large and original passages of William archbishop of Tyre, (l. i. c. 1 - 10, l. xviii. c. 5, 6,) the principal author of the Gesta Dei per Francos. M. De Guignes has composed a very learned Memoire sur le Commerce des Francois dans le de Levant avant les Croisades, etc. (Mem. de l'Academie des Inscriptions, tom. xxxvii. p. 467 - 500.)