Sheikh Ahme Ismail Yassin (1937–2004 (aged 66–67)) (Arabic: الشيخ أحمد ياسين) was the co-founder, with Abdel Aziz al-Rantissi, of Hamas, a militant Palestinian political organization. Yassin served as the spiritual leader of Hamas, an Islamist Palestinian group that has often been characterized by western states as a terrorist organization.