In 1200, Alaaddin Takesh died and was succeeded by his son, Alaaddin Mohammad, who by 1205 conquered the remaining parts of the Great Seljuk Empire, proclaiming himself Shah. He eventually became known as the Kharazmshah. In 1212 he defeated the Gurkhan Kutluk and conquered the lands of the Kara Khitay, now ruling a territory from the Seyhoon almost all the way to Baghdad, and from the Indus River to the Caspian Sea.In February 1220 the Mongolian army crossed the Seyhoon, beginning the Mongol invasion of Persia. The Mongols stormed Bokhara, Samarkand, and the Kharazm capital Urgench. The Kharazmshah fled and died some weeks later on an island in the Caspian Sea.