According to an article from scholar Hadia Dajani-Shakeel:
Al Sulami defined the Crusade as an invasion by Western nations, which started with the conquest
of Sicily and parts of al Andalus. The same nations, having encountered the weakness of the Muslims
in the West and heard reports about their disunity in the East, marched against the East, while their
ultimate goal was the conquest of Jerusalem. This definition of the Crusades by al Sulami appears to
have escaped many modern historians, who allege that the Muslims underestimated the the nature
and motives of the Crusades in the twelfth- century. Al Sulami, who preached in Damascus until
his death, interpreted the Crusade as a divine warning to test the willingness of the Muslims to refrain
from committing acts that God forbade and to undertake the duty of jihad, which they had neglected.
He warned his contemporaries that if they did not act immediately, while the enemy was still weak
and far from his sources of supply, they would not be able to uproot him. (1)
[Continued...]
University of British-Columbia scholar Dr. Niall Christie is currently producing a full annotated edition and translation of the Kitab al Jihad for a collaborative work with Dr. Debra Gerish of Emporia State University. The work will provide an analysis and comparison of al Sulami's work with Pope Urban II's calling of the First Crusade. For more information, see the University of British Columbia projects page.
1. Hadia Dajani Shakeel- Some Medieval Accounts of Salah al Din's Recovery of Jerusalem (Al Quds) Internet History Sourcebooks.