Excerpts from Books and Wikipedia
"Sometime in the late summer, a visitor arrived at the Crusader camp on the Nile: Francis of Assisi, founder of the order of the Lesser Brothers. . . . where he hoped to bring peace to the Crusade-wracked country by converting the Sultan. . . . Francis then set out for Cairo and eventually gained an audience with al-Kamil himself. By this time, al-Kamil had managed to put down the rebellion in the capital . . . He received Francis politely and listened to his sermons. (“In fact,” Jacques de Vitry adds, “the Saracens willingly listen to all these Lesser Brothers when they preach about faith in Christ and the Gospel teaching, but only as long as in their preaching they do not speak against Mohammed as a liar and an evil man.”) The new sultan was ultimately unconvinced, but he dismissed Francis of Assisi with unfailing courtesy, and had him escorted safely back to the camp at Damietta." [Bauer: renaissance World, p. 277] "Al-Kamil (…) was a Muslim ruler and the fourth Ayyubid sultan of Egypt. During his tenure as sultan, the Ayyubids defeated the Fifth Crusade. . . . As a result of the Sixth Crusade, he ceded Jerusalem to the Christians and is known to have met with Saint Francis." [Wikipedia]