of the Oxus, he set out for his capital, but on reaching Merv he was so heartbroken at the desolation that met his eyes that he sickened and died.[333] The ruins of his splendid mausoleum are the chief glory of ancient Merv. It was built by him during his lifetime; and so great was its solidity that he gave it the name of _Dār ul-Ākhirat_, “the Abode of Eternity.” Sixty years after his death it was destroyed by Chingiz Khān. CHAPTER XX THE KHWĀRAZM-SHĀHS On the death of Melik Shāh in A.H. 485 (1092) a civil war broke out between the brothers Berkiyāruk and Mohammad, which resulted in the formation of separate semi-independent states, under various branches of the Seljūks, in different quarters of the dominions of that family. Chief among their representatives were--the Seljūks of Kirmān, A.H. 433–583 (1041–1187); the Seljūks of Syria, A.H. 487–511 (1094–1117); the Seljūks of `Irāk and Kurdistān, A.H. 511–590 (1117–1194); the Seljūks of Rūm (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 Khorāsān. On his death in A.H. 552 (1157) the authority of the great Seljūks came to an end, and Khorāsān fell into the hands of the Khwārazm-Shāh, Il-Arslān, who had succeeded his father in the previous year. In 567 (A.D. 1171) the Kara-Khitāys advanced into Khwārazm, and Il-Arslān marched out to oppose them; but on reaching Amūya[334] 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 Khwārazmians the Kara-Khitāys again withdrew, A.H. 568 (1172).[335] In the following year Il-Arslān died, leaving his realms to his youngest son, Sultan Shāh Mahmūd. His elder brother Tekish, however, disputed the succession, and, with the aid of the Kara-Khitāys, overthrew the young prince and set himself upon the throne, A.H. 568 (1172).[336] Sultan Shāh Mahmūd, with his mother, Queen Turkān, fled to Nīshāpūr, and sought the aid of its governor, Mu`ayyad. Reinforced by a contingent under his command, Sultan Shāh made a fresh bid for sovereignty. Tekish advanced to meet him in the desert of Khwārazm, and inflicted a crushing defeat on his brother. The queen-mother was slain, and Mu`ayyad was captured and cut in two. Sultan Shāh escaped a similar fate by flight, and found safety among the Ghūrides of Ghazna.