The later 'Abbasids (1152-1258)
With the death of Muhammad Tapar, the Great Seljuq state was in effect partitioned between Muhammad's brother Sanjar, headquartered at Marw in Khorasan, and his son Mahmud II (1118-31), centred on Hamadan in Persian Iraq. These Iraq Seljuq sultans tried unsuccessfully to maintain their control over the 'Abbasid caliph in Baghdad, but in 1135 the caliph al-Mustarshid (1118-35) personally led an army against the sultan Mas'ud, although he was defeated and later assassinated. Al-Mustarshid's brother, al-Muqtafi (1136-60), was appointed by Sultan Mas'ud to succeed him as caliph. After Mas'ud's death, al-Muqtafi was able to establish a "caliphal" state based on Baghdad by conquering Al-Hillah, Al-Kufah, Wasit, and Tikrit.
By far the most important figure in the revival of independent caliphal authority in Arabian Iraq and the surrounding area--after more than 200 years of "secular" military domination, first under the Buyids and then the Seljuqs--was the caliph an-Nasir (1180-1225). For nearly half a century, he tried to rally the Islamic world under the banner of 'Abbasid universalism, not only politically, by emphasizing the necessity for the support of caliphal causes, but also morally, by attempting to reconcile the Sunnites and the Shi'ites. In addition, he tried to gain control of various voluntary associations such as the mystico-religious (Sufi) brotherhoods and the craft-associated (futuwah) organizations. He also began the dangerous precedent of allying himself with powers in Khorasan and Central Asia against the traditional caliphal adversaries in Persian Iraq. Through this policy, he was able to rid himself of the last Iraq Seljuq sultan, Toghrl III (1176-94), who was killed by the Khwarezm-Shah 'Ala' ad-Din Tekish (1172-1200), the ruler of the province lying along the lower course of the Amu Darya (ancient Oxus River) in Central Asia.
When Tekish insisted on greater formal recognition from the caliph a few years later, an-Nasir refused, and inconclusive fighting broke out between the two. The conflict came to a head under Tekish's son, the Khwarezm-Shah 'Ala' ad-Din Muhammad (1200-20), who demanded that the caliph renounce the temporal power built up by the later 'Abbasids after the decline of the Iraq Seljuqs. When negotiations broke down, Muhammad declared an-Nasir deposed, proclaimed an eastern Iranian notable as anticaliph, and marched on Baghdad. In 1217 Muhammad seized most of western Iran, but, just as he was about to fall on an-Nasir's capital, his army was decimated by a blizzard in the Zagros Mountains. These events afforded an-Nasir and his successors only a brief respite from dangers arising in the east.
