 Oljeitu , also named Mohammad <unk> , was great @-@ grandson of Ilkhanate founder Hulagu , and brother and successor of Ghazan . In his youth he at first converted to Buddhism , and then later to Sunni Islam with his brother Ghazan , and changed his first name to the Islamic Muhammad . In April 1305 , Oljeitu sent letters to Philip IV of France , Pope Clement V , and Edward I of England . As had his predecessors , Oljeitu offered a military collaboration between the Mongols and the Christian nations of Europe , against the Mamluks . European nations prepared a crusade , but were delayed . In the meantime Oljeitu launched a last campaign against the Mamluks ( 1312 – 1313 ) , in which he was unsuccessful . A final settlement with the Mamluks would only be found when Oljeitu 's son Abu Sa 'id signed the Treaty of Aleppo in 1322 . 
