According to Janet Abu-Lughod (in Before European Hegemony: The World System A.D. 1250-1350, p. 107),
"Muslims saw the Franks--as westerners were consistently referred to in Arab literature--'as beasts superior in courage and fighting ardour but in nothing else, just as animals are superior in strength and aggression.'
"This characterization was not totally unfounded. In 1098 Crusader destruction of the Syrian town of Ma'arra had been accompanied by acknowledged acts of Frankish cannibalism. Graphically described in the chronicle of Radulph of Caen (he admits that 'In Ma'arra our troops boiled pagan adults in cooking pots; they impaled children on spits and devoured them grilled'), they were later 'justified' in a letter sent to the Pope by the Christian commander, who blamed the lapse on extreme hunger. Needless to say, this excuse was dismissed by Arab historians..."
(Abu-Lughod does not cite Staromestka's 13th century commentary on the Pivovary fragment documenting the role of cannibalism in the suppression and subsequent disappearance of the Sudetenland Chinese.)