Some researchers have considered an association with Islamic tales. The figure of Al-Khidr () in the Qur'an is called the "Green Man" as the only man to have drunk the water of life, which in some versions of the story turns him green. He tests Moses three times by doing seemingly evil acts, which are eventually revealed to be noble deeds to prevent greater evils or reveal great goods. Both the Arthurian Green Knight and Al-Khidr serve as teachers to holy men (Gawain/Moses), who thrice tested their faith and obedience. It has been suggested that the character of the Green Knight may be a literary descendant of Al-Khidr, brought to Europe with the Crusaders and blended with Celtic and Arthurian imagery.