On the death of Melik Shah in A.H. 485 (1092) a civil war broke out between the brothers Berkiyaruk and Mohammad, which resulted in the formation of separate semi-independent states, under various branches of the Seljuks, in different quarters of the dominions of that family. Chief among their representatives were—the Seljuks of Kirman, A.H. 433–583 (1041–1187); the Seljuks of Syria, A.H. 487–511 (1094–1117); the Seljuks of `Irak and Kurdistan, A.H. 511–590 (1117–1194); the Seljuks of Rum (or Asia Minor), A.H. 470–700 (1077–1300). Until the death of Sanjar the main branch preserved a nominal suzerainty over the rest, although their empire had been so greatly reduced that Sanjar’s rule was practically confined to Khorasan. On his death in A.H. 552 (1157) the authority of the great Seljuks came to an end, and Khorasan fell into the hands of the Khwarazm-Shah, Il-Arslan, who had succeeded his father in the previous year. In 567 (A.D. 1171) the Kara-Khitays advanced into Khwarazm, and Il-Arslan marched out to oppose them; but on reaching Amuya334 he fell dangerously ill, and was obliged to resign command of his army to one of his generals. After gaining a decisive victory over the Khwarazmians the Kara-Khitays again withdrew, A.H. 568 (1172).335 In the following year Il-Arslan died, leaving his realms to his youngest son, Sultan Shah Mahmud. His elder brother Tekish, however, disputed the succession, and, with the aid of the Kara-Khitays, overthrew the young prince and set himself upon the throne, A.H. 568 (1172).336

Sultan Shah Mahmud, with his mother, Queen Turkan, fled to Nishapur, and sought the aid of its governor, Mu`ayyad. Reinforced by a contingent under his command, Sultan Shah made a fresh bid for sovereignty. Tekish advanced to meet him in the desert of Khwarazm, and inflicted a crushing defeat on his brother. The queen-mother was slain, and Mu`ayyad was captured and cut in two. Sultan Shah escaped a similar fate by flight, and found safety among the Ghurides of Ghazna.

Tekish337 was, in A.H. 588 (1192), firmly settled on the throne of Khwarazm. Confident in the devotion of an army which he had led to victory, he grew ambitious and forgot the obligations under which the Kara-Khitay had placed him. He incurred the wrath of that powerful tribe by putting to death one of their envoys who had come to claim the annual tribute, and brought them into the field against him. On learning that his brother was sorely beset, Sultan Shah left the protection of the Ghurides and joined the Kara-Khitays, whose queen he persuaded that the Khwarazmians were anxious for his return to the throne. As the Queen-Gur-Khan was incensed against Tekish, she allowed herself to be gained over by Sultan Shah, and sent her husband Karma338 with a large force into Khwarazm to defend the rights of Sultan Khan. Tekish, hearing of their advance, commanded the waters of the Jihun (Oxus) to be diverted across their line of march, so that the progress of the Kara-Khitays was rendered almost impossible. Meanwhile he busied himself with military preparations. Karma, seeing clearly that Sultan Shah’s pretensions to the esteem of the Khwarazmians were unfounded, led his army home. Sultan Shah, with his own followers and a small body of Kara-Khitays, marched to Sarakhs, and, evicting its governor, established himself there.

In A.H. 576 (1180) we find him at the head of 10,000 horsemen, and lord of Nishapur. In A.H. 582 (1186) Tekish set out for Khorasan with a large army; while Sultan Khan hastened to Khwarazm by another road. These hostilities between the two brothers continued with only short intermissions until the death of Sultan Shah in A.H. 589 (1192), when Tekish became master of all Khorasan and Khwarazm.339

In A.H. 590 (1194) he entered Persian `Irak and overthrew Toghrul III., the last of the great Seljuks of Persia.340 After adding Ray, Isfahan, and other important towns to his dominions, he obtained an investiture from Caliph Nasir li Din-illah of all the countries which he had conquered. From this epoch-time till his death Tekish appears to have paid tribute regularly to the Gur-Khan, and retained his friendship. He recommended his son and successor to follow the same policy, for the Kara-Khitay were a bulwark against the dreaded hordes of the East.341

In A.H. 596 (1200) Tekish died, and was succeeded by his famous son, `Ala ud-Din Mohammad, who soon made himself master of Khorasan, Balkh, Herat, Mazenderan, and Kirman.342 He now considered himself sufficiently powerful to assert his independence of the Gur-Khan, to whom, like his three predecessors, he had paid an annual tribute. He was encouraged to resist his liege lord by `Othman, prince of Samarkand and Transoxiana, who was also a vassal of the Gur-Khan, who promised to pay him the same allegiance as he had rendered to the Kara-Khitays in return for his assistance against the common enemy.343 An occasion for the rupture of friendly relations between the Khwarazm-Shah and the Gur-Khan was soon found. It was identical with the method employed by Tekish,—the slaughter of one of the receivers of tribute.344

After perpetrating this outrage, Mohammad entered the Kara-Khitay territory, A.H. 605 (1208), where he suffered a crushing defeat and barely escaped capture.345 In the following year Mohammad made a second incursion into the land of the Kara-Khitay. Crossing the Jaxartes at Finaket, he gained a signal success over their general, Tanigu, beyond Taraz, pushed his conquests as far as Otrar346 (Farab), and returned in triumph to Khwarazm. But the tangled knot of Central Asian politics was soon to be cut by a conqueror whose annals are as devoid of complexity as his career. In the place of paltry struggles for supremacy in isolated states, attended by obscure and ever-changing fortunes, we have the triumphant advance of one who, like Alexander of Macedon, was destined to give a new impulse to the world’s history.