MUSTA'SIM, AL-

born 1212 died 1258 the last 'Abbasid caliph in Baghdad (reigned 124258). Ineffectual himself and surrounded by advisers with conflicting opinions, al-Musta'sim presented no strong defense against the Mongol conqueror Hleg, grandson of Genghis Khan. Al-Musta'sim ignored several demands of Hleg and answered others with blustering and empty threats. Finally Hleg laid siege to Baghdad in 1258 and entered the city in February of that year. The caliph and 300 officials hurried to present their surrender and, 10 days later, were all put to death. This left Islam without a caliph for the first time in its history. Hleg burned and plundered the city, killed many of its inhabitants, and later invaded Syria and then returned to Persia.