 For Asiatic Christians , the fall of Baghdad was cause for celebration . Hulagu and his Christian queen came to be considered as God 's agents against the enemies of Christianity , and were compared to the influential 4th @-@ century Christian Emperor Constantine the Great and his revered empress mother , Saint Helen , an icon of the Christian church . The Armenian historian <unk> of <unk> praised the Mongol royal couple in texts for the Armenian Church , and Bar Hebraeus , a bishop of the Syriac Orthodox Church , also referred to them as a Constantine and Helena , writing of Hulagu that nothing could compare to the " king of kings " in " wisdom , high @-@ mindedness , and splendid deeds " . 
